This seems like a slightly less insidious (and, arguably, less fun) version of a common drinking game from my college: text or shot. You take turns with a random person's phone, composing a text to a person of your choice -- you show the (unsent) message to the owner of the phone and they can either elect to send the message or take a shot.

(As one might imagine, this is the kind of game that grows even better over time.)