I went out to practice my slow manuvers and was doing pretty good. I did my weaves, RH uturn, swerve and quick stops. I was building my confidence cause I couldn't do some of these prior to reading this website...thanks for the great advice. Anyway, I rode home and went ahead and started practicing the quick stops again. Well I did one between 5 - 10 mph and did good. Tried it again, stopped, and it was like a cartoon

...I had both feet on the ground, the bike on level ground (more or less) and then the bike slowly went down on top of my left leg.

Can anyone explain to me why it would do that? I know it's silly, but for the life of me, I can't figure out why it happened.
Thanks.