That's an illegal move, but it's brilliant.
This is pretty much the kindest practical joke a group of friends has ever played on the first person to pass out at a party. Sure, it's possible they were just out of Sharpies. Or poorly drawn forehead dicks aren't cool anymore (UPDATE: I asked some college kids and poorly drawn forehead dicks are still cool). Or maybe this is a creative, intellectual bunch who just don't find cruelty humorous.
Evidently, they took the time to put their sleeping friend in the "recovery position" first, which shows a certain amount of maturity and consideration. Whatever their reasons for not taking advantage of a potential victim, I applaud their ingenuity and class.