Definitions by Two Girls One Cup

Bucking Filly 

The art of fucking a girl from behind (vaginally) and then pulling out and forcefully sticking it in her ass thus causing her to kick backwards in a bucking fashion. The bucking will normally be in the old nutsack area which may be pleasureable to some men.

I've always wanted to date an equestrian, but I am afraid she may be a bucking filly.

Bucking Filly by Two Girls One Cup December 21, 2009