Cum sister

A girl you call one of your own because you both have fucked the same guy.

"Hey, I had sex with mike before you did!"
"I know! Love you cum sister!"

by tooflirty22 December 12, 2009

Cum sisters

Two girls, one dick. When more than one girl have sex with one guy.

These two chicks are cum sisters because they both fucked James.

by Taliasmash September 14, 2016