During or after sexual intercourse, while your "partner" is in the cowgirl/reverse cowgirl position you unceremoniously back hand them to the bedroom floor or parking lot, depending on where the coitus is occuring.
Second definition:
While having sex in a plane or on top of a high cliff vigorous thrusting causes your partner to go ass over tea kettle.
Topended:
Becca was glad she had gone for the gold health plan at work. Getting "topended" into a moped will surely require stitches'.
Topending:
Marsha was only a flight attendant and wasn't suppose to jump with the other skydivers. However, "topending" is what she received from a randy instructor. Thankfully her fall to earth was short and filled with orgasms.
Topend:
Not being one to consider the needs of others, Bob would often "topend" his partner as soon as he busted a nut.
Ruler of Lake Titicaca. Rumored to have a bunghole that gets very angry if it does not receive toilet paper. Cornholio the Great is often seen walking around with his shirt over his head and his hands in the air, chanting songs about his power, and his bunghole.
"I am Cornholio! You do not want to face the wrath of my bunghole, for I need TP!"
Butthead: Shut up, Beavis! (uh huh huh huh)
Beavis: Um, okay. (heh heh heh heh).