"She was so busy mooning over her professor she didn't even realize class was over"
To invite someone over to watch movies with the intention of hooking up with them.
Moonies are most likely held in a smaller more cramped room. It is unusual for the female party to know about the boys intentions.
Bart: What you watching?
Sam: 5 minutes of Step Up, then 2 hours of her
Lebron James is to basketball like Moony is to spamming.