Tap water consumed on a night out as a substitute for alcohol, usually drunk on it's own but sometimes drunk alongside alcoholic beverages.
Guy A: Sup dude, what you drinking there?
Guy B: It's a happy tappy dude.
Guy A: Man I'm thirsty, but I don't want to get drunk.
Guy B: Hey try this, it's a happy tappy.
Guy A: Whoa, this is super refreshing!
Guy B: I know right!
Guy B: It's a happy tappy dude.
Guy A: Man I'm thirsty, but I don't want to get drunk.
Guy B: Hey try this, it's a happy tappy.
Guy A: Whoa, this is super refreshing!
Guy B: I know right!
by UnclePhilip July 6, 2012
by WD40/car August 2, 2008