|1.||I'm just pissing on you're tits|
Usually followed by a joke or an untruth to show you were just kidding; it's kind of like saying "I'm just yanking you're chain"
Guy 1: "Hey man, you're girlfriend gave me head last night"
Guy 2: "What?! Are you serious?!"
Guy 1: "Nah, I'm just pissing on you're tits haha"