The act of two men having a secret conversation in front of the person they are talking about without actually saying more than around 6 words, instead the words are replaced with a series of head nods, bobs, tilts and eyebrow raises.
Me: Dude are you... "Head bob" You know... "Raises eyebrow in direction of chick"
Other guy: Huh?
Me: You know... "tilts head at girl while raising eyebrow"
Other guy: Oh... "Head nod" :D
Rouglhy translated as
Me: "Dude are you hitting that fine assed pussy?"
Other guy: "Which one dude, I know not which poon you speek of"
Me: "You know the one over there, around 5'10", long blonde hair, blue top with white stripes and a brown bag"
Other guy: "Ohh... Yes my friend I am indeed sleeping with that fine young lady, she is indeed very good and does all the nasty stuff we all dream of"