We aren't sure, we only know that, there is no cure...

When the seat is removed from a bicycle leaving only the seatpost. So when you ride the bike the seatpost goes up your rectum or vagina.

verb: something akin to a texas chili bowl, involving a bike wheel, sausage, and an anus/grundle. One inserts the sausage into another's anus and spins the wheel to give the person's grundle an indian sunburn.

A polish bike ride is when a man lays on his back and his partner, a woman or a homo, sits on him like a bike without a seat. Thus the asshole is penetrated and the rider make motion as if they were pedaling.

When a man is having sex with a woman from behind, he grips her waist,lifts his feet and starts kicking her in the breasts.

The act of shoving your knee cap into someones anus consensually and or against there will

A Polish Bike ride is when you are sexually inclined with that special someone and then go doggy style and you sit back as to recline in such a relaxed motion that you start kicking her in
the titties and forget what you were even there for.