the phrase "balls deep" comes from pinball machines. when you want to launch the ball full force you pull the plunger all the way back, otherwise known as going, "balls deep."

no just kidding that one actually means what you think it does

sinking two balls into the same cup while playing beer pong. making the incredible shot will reward you with three cups being removed and both balls back to shoot again.

1. To literally have a dick inside you as far as it can go.

2. To be very into something.

3. To be concentrating hard.

Being dead serious

To be really fucking high.

Balls-Deep is the point when your testicles reach cold water while swimming thus making your testicles shrink into themselves.

the girl equivelent would be Clit-Deep

While bowling, if you throw a gutter ball for your first throw, then throw a strike to pick up the spare on your second ball.