Definition
A poker hand in Texas hold 'em, consisting of two nine cards.
Origins
A pun on nine nine and German nein nein (“no, no”).
How People Actually Use It
In Texas holdem, when a player is dealt pocket nines, he is said to be holding a german virgin.
"Guy: Hey you dumb kraut, lets have sex. German Virgin: NEIN, NEIN!!!"
Source: Urban Dictionary