For anyone not familiar with the terminology, I'm referring to bike trainers:
These lovely little machines simulate road resistance when the elements outside are just too much to handle. They can also make your butt, balls or lady parts numb during the experience. This numbness doesn't really affect much, it'll wear off and tingle in that not so desirable way.
However if you're a lady and you have a little bump and grind before a trainer ride, you might as well forget those miles. Sticking a hard item up your yoo-hoo and then following it up by putting all your weight on said hoo, is a terrible...let me say it again, TERRIBLE, idea. A word from the wise... leave the candles and baby makin music for after your spin.