I have seen the same technique many times with folks on bicycles. However the reason in such instances over here, was not for the purposes of a Kids game. I remember seeing it being done as a child and trying it myself with disastrous consequences the first time. The folks (of all ages) who I saw doing it, had a good reason. They were masterful at it. Such skill came from riding bicycles with badly worn brake blocks. It was easier for them to slow the bicycle as much as the blocks would allow while standing on the left pedal, and then jump off and trot to a halt for the last few yards. I thought it looked easy...........as kids im sure we did that on a made up game of races a kind of push bike relay when there was maybe 6 kids and just 2 bikes as one was getting off the next kid was getting on and the bike never properly stopped.