A slam sack is a body used for fucking. This usually refers to females, but has come to encompass anyone who fits the description.

When someone with a tiny penis "try's" to masturbate. Their peter is so tiny that they end up just slapping their sack

The act of taking a plastic grocery bag and cutting a hole in the bottom, inserting your penis through the hole. Then apply a condom overlapping the bag at the base. For removal grab grocery bag handles and pull all of the diseased fluids, dead children, and regret away, it will be easily discarded...

Literally, slower than a sack of shit moving down the runway.

1) The act of constantly abusing your genitals to pleasurable thoughts
2) Slang for playing the game of Hacky Sack

Something that is the pinnacle of greatness in any category.

When the scrotum sack is put in between the lip and bottom jaw like dip then swished around.