Stands for "What would Teresa do?"...she's the phunky bitch who has no dating fear or shame. This phrase should be used in bars and other pick-up places when one is feeling shy or scared to approach a guy. In these situations, one can use the basic pick-up line "Hey, gotta girlfriend? Wanna go out?" etc.
Two girls in a bar, staring at some hot dude a few tables down.
Girl #1: "I can't do it. I just can't do it.
#2: "Just go say hi...just walk up to him and say hi!"
#1: "I don't think I can do it."
#2: "Dude. WWTD?"
#1: "You're totally right. I'm going."