The secret is to have the person "fall off" the skid rather than "jump". If they jump the sudden downward force from their feet on the skid followed by the sudden loss of weight as they depart the scene causes some interesting oscillations!
Done carefully(if this is possible!) it doesn't cause too many problems for the R22 or R44. In the R22 make sure the pilot is not too fat. It does however cause a few problems for the jumper if he misses the animal. One of my regrets in life is that I didn't have a camera rolling when some of these blokes launched - the most dangerous part of the entire operation is trying to gain height & keep your eye on the entertainment all while pissing yourself laughing!