There's not really any trick to riding a giraffe. It's basically like riding a normal unicycle once you get up high enough to ride it.
The main problem in mounting is getting height. There are several ways of cheating to get height, some of which may involve breaking rules.
The Picnic Table (Garbage Can, Car Hood)
This is a way of applying the normal rollback or static mounts to a giraffe. A typical picnic table is probably sufficient height for a 5 foot giraffe; for a larger giraffe, you may want to find a larger object to serve as a picnic table substitute.
The procedure is simple - stand on the edge of a picnic table, with the giraffe in front of you with it's wheel on the ground. Mount as you would a smaller unicycle on the ground. Bear in mind that you have an uneven surface to fall on if you go backwards, so pushing off the table too hard is infinitely preferable to pushing off too softly.
The High Fence/Wall
This mount works for any giraffe height, depending on the availability of fences. Hang the giraffe by the seat on the fence. Climb up the fence and sit on top. Then rearrange yourself so you have a foot on a pedal and your bum on the seat. Finally, transfer your weight from the fence to the unicycle. This mount is both the least scary and the least elegant.
The Tree Branch
This mount again works for any height of giraffe, provided that you have suitable branches available. Climb the tree to the required branch, then hang from that branch by your hands. Have a friend pass the giraffe; grab it with your legs and arrange things appropriately, then ride away.
This is the most obvious method, but also the hardest of the assisted mounts. Hold the unicycle upright, with a pedal in the 6 O'Clock position. Put one foot on the pedal, and hold the seat with one hand and the pole with the other. Haul yourself up, using the pole for stability. Depending on the height of your unicycle, you might need to start by climbing onto the tire, and then bringing your foot up to the pedal. Sit on the seat and ride away.
Climb up your friend and the giraffe at the same time. Then shift your weight from the friend to the unicycle and ride away.
A good friend or person without any ambitions is required.
This is where it gets especially interesting, because you are basically climbing up a moving object.
This is the best method of free mounting a giraffe of 6' or more. Put the right pedal at 6 0'Clock, and put your left foot on top of the wheel and push your foot into the fork. This locks the wheel and pedals in place. Step up and put your right foot on the right pedal, then put your weight on the pedal - this stops the wheel from moving much. You should now be able to move the left foot from the wheel to its pedal and sit on the seat, at which point you should be in a position to ride away. The climb has to be just right so that you end up leaning forwards as much as is required to ride away. Before working on this mount, you should be able to do the side mount on a regular unicycle, because once you get your left foot on the pedal and stand up on it, this mount works the same as the side mount. You should also practice mounting the giraffe this way while holding onto something, until you can get on fairly quickly, and without putting too much weight on your support.
Some sizes of giraffe can only use this mount if the giraffe has pegs on the frame that act as brakes when they are pushed down.
This works quite well for tall people and 5' giraffes, and has been known to work for 6' giraffes. Put one pedal at the 6 O'Clock position and one foot on the pedal. Hold the seat with both hands. Do one smaller hop, then one huge hop, with the foot on the ground. That should get you high enough that you can push yourself upwards with your hands on the seat and the foot on the pedal, which should in turn get enough height that you can put your bum on the seat and other foot on the pedal, and ride away.
A loose sprocket on your hub can cause serious problems with this jump. When applying such intense forces on the crank, the sprocket on the hub can slip and cause the rider to fall down. Once the sprocket gets loose, it must be tightened or else it may effect normal riding, especially when it slips while idling. Use thread lock on the sprocket to prevent further slipping. You can also weld the sprocket to the hub for a more permanent solution.
Also known as the frog mount, the Jump mount is one of most difficult ways to mount a giraffe. Start by holding the giraffe in a vertical position, with the pedals horizontal. Hold the back of the seat with both hands, thumbs on top. In one motion, jump up as high as possible and land on the pedals. If the wheel rolls at all during the jump it will be almost impossible to judge where the pedals will be. This mount is much easier to land seat out, where you can begin hopping or riding seat out. Another way to make the mount easier is to hold the unicycle at approximately waist level, and then raise it to vertical during the motion of the jump.
This a scarier, but probably also more impressive way to mount a giraffe. While it works best for shorter giraffes, it can be done on a 6' giraffe. Simply run along while holding the giraffe with the saddle a little above crotch level, then at exactly the right moment, launch youself onto one pedal, and then the seat and other pedal simultaniously. It is advisable to land with almost all of your weight on the back pedal. This will allow you to pedal backward a few cycles of the wheel in order to get the wheel under you. With practice you can jump higher and apply less pressure to the first pedal, eliminating the need to roll back. The main difficulty with this mount is getting your first foot on the pedal at exactly the right moment. You want to hit it while it's coming up, so that you will press downward on the pedal and make the unicycle roll under you. One other thing to remember is make sure you take a fairly fast, confident jump. Think of it like pole-vaulting.
A great number of unicycle skills can either be taken directly from their respective genres or translated into more reasonable skills to account for new factors that must be taken into account for a giraffe.
One Footed Idling
Idling with one foot one the giraffe, after being able to idle well, is fairly easy. It is easier to idle with one foot on the giraffe then on the standard unicycle, so if you can't idle to great one footed on your regular unicycle it is still worth a try. It is easiest with the bottom of one foot pushing against the front of the frame, but it looks better with one foot extended witch isn't much harder. It is also possible to one foot idle with the non pedaling foot on your opposite knee, putting your non pedaling foot on the opposing top of crank, and holding the foot, knee, or leg in your hand.
One Footed Riding
Riding with one foot is not much harder then on a normal unicycle. When first learning it is best to be able to one foot idle well in the technique you would like to ride which would most likely either be with your foot against front of frame, or with it extended. Be sure to fall off the unicycle forwards to avoid a landing on your back, while practicing one footed riding, because it is very likely your foot can get caught by the pedal or the sprocket.
Seat in Back Riding
For this trick it is best to lower the seat slightly to make it easier to put the seat from under you to behind you. Unlike seat in back riding on the normal unicycle it is much easier to ride with both hands firmly on the seat because of the difference in weight. You have to lean forward a ways, and hold the seat pretty close behind you.
Hopping on a giraffe is the same as a standard unicycle: stand, firmly grasp the handle or front of the giraffe, and jump with the unicycle. There are two important things to consider when hopping on a giraffe. First, the giraffe weighs far more than the average unicycle. Secondly, when the giraffe starts to tip one direction, your weight on the pedals is transferred to the frame in a way that accelerates your fall. This is a non-issue for a standard unicycle, where you apply no weight to the frame when hopping.
Hopping seat out is the same as a normal unicycle, except the tipping effect described above is magnified by the intentional tilt of the frame. This can be compensated for by bending at the waist and placing your center of gravity farther back than usual.
Rolling hops on a giraffe are more difficult because of the large weight of the frame. Fortunately, the giraffe has an inherent benefit that helps compensate for this. When approaching the point at which he plans on jumping a giraffe rider can allow himself to fall forward more than usual. Because of the height of the frame the rider can be a foot or more in front of his intending take-off point before the wheel leaves the ground. The rider now jumps, and if he jumps with the pedals approaching horizontal but not yet there he can use his waist and legs to push the giraffe out in front of him. He now lands with the unicycle tilted backwards, and takes advantage of his momentum to reassume his original position above the cranks. Using this technique it is not uncommon for a giraffe rider to clear gaps of 2 feet or more with their body at almost the same point in the air for the time period in which the wheel is in the air.
A wrap can be performed on a giraffe in a similiar way to a standard unicycle. This includes double wraps, triple wraps, super wraps, and so on. It should be noted that it is harder to recover from a wrap for the tipping issue mentioned above.
The giraffe spin is the same as a unispin on a standard unicycle. Start by hopping seat out (see above) with both hands on one side of the seat. For the 180 Giraffe Spin, jump off of the pedals and spin the giraffe so that you land on the pedals with the unicycle backwards. Important differences are that your feet do not need to clear the tire, but landing on the sprocket becomes a problem.
There are a few riders who can do the "side-ride" on a tall unicycle.
Playing a Musical Instrument
An assortment of instruments work well in conjuction with a giraffe unicycle. These include in part electric guitars and basses (with mini-amps), vocals, woodwind, and brass instruments (yes, unicycling with a tuba is quite possible). It is advisable to first mount the unicycle before picking up any such instrument to avoid personal injury and/or injury to one's instrument. For this reason, one should always use the oldest and most decrepid of musical instruments when attempting this stunt. An assistant is usually necessary when performing such a stunt, preferrably one who has the physical capability of lifting a moderately large instrument and performing such tasks as opening doors. Believe it or not, these can be hard to come by outside of the unicycling world.
Remember that when you are on a 6 foot giraffe, you are almost 7 feet off the ground. A fall from this height could result in injury. Be sure to be fully equipped with safety gear. A spotter is highly recommended for learning how to ride a giraffe.
The most important factor of giraffe riding is the fact that your weight rests on the frame instead of the hub. If the unicycle is not exactly vertical your body weight accelerates the fall of the uni, and this can cause unfamiliar movements to a novice giraffe rider. This can be referred to as the tipping effect.When sitting on the giraffe this is usually negated by your body on the seat, but when performing seat out skills or mounting it plays a role in the movement of the giraffe. It is important to think through all skills you plan on attempting and analyzing how the frame will be tilted at any given time.
An ideal way to fall off is forwards. It's easier than you think; basically, you start the unicycle toppling over and take your feet off the pedals; the wheel will move backwards a short way, and the seat (and you) will move forwards and down until you hit the ground. Bend your knees when you land and you'll be surprised at how little pain is involved.
This is by no means the definitive opinion on the matter of giraffe dismounts. There is a school of thought that holds it to be safer to dismount to the rear and have the giraffe move forwards as you drop to the ground and a safe landing on your feet.
Safety is the main reasoning behind this line of thought. If you dismount and allow the wheel to move backwards, there is a chance that it might stop short against a wall, pavement or (despite your best intentions and checking over your shoulder before comitting to the dismount) a pedestrian who walked into the path of the rearward travelling giraffe. Such a stop can cause severe injury as the force will be transmitted to your spinal column via your coccyx.
This is topic that bears some discussion and this discussion can be joined here.
The rider is encouraged to investigate this issue and make a personal decision.
A major issue concerning giraffe safety is the strength of the frame. Due in part to the generally cheap construction and the large size it is not uncommon for giraffe frames to bend or even snap. Skills such as rolling mounts apply forces in three places (up on the handle, down on the cranks, and up on the tire) in such as way that the frame experiences extreme stress. Until giraffe construction is rethought to allow for more intense riding it is advisable to check your frame every time you ride to assess the state of your frame. It is up to you to make a judgement concerning the safety of your frame.