Vacation Pothead
Any regular person, who usually only smoked weed a couple of times in his life, but once going on vacation, will think of nothing else but weed, and will smoke any chance he can.
Eric: I've never smoked before, but man, this is Ibiza! We gotta get high!

Jake: Man, you're a real vacation pothead

(two hours later)

Eric: Let's smoke again!