Comes from the internet porn clip 'Aww nigga' and is used to describe the actual act of putting your testicles in a girl's ass and your dick in her pussy.
"Aww man freak that bitch out antone!" "Clam that bitch!"
"Nuts in da ass, dick in the pussy!"
The illusory idea that homosexual women may have sex by bumping one female's vaginal labia against another female's vaginal labia. A slander. Other forms: clam bumper(s).