When kneeling behind a woman bent over, doggy style, sticking 2 fingers in the woman’s vagina, and 1 in the anus. Similar to how one would hold a bowling ball.
A sexual act where a female gets into the fetal position and their partner sticks his/her thumb into the female's anus and thier middle and ring fingers into the females vagina. After the insertion is completed, the female must be lifted and brought to the nearest stairway and be rolled down the stairs, just like a bowling balldown the lane, hence the name "filthy bowler"