I want to stay out all night but I need a great excuse... Any suggestions?

So here the scenario: it's prom night and I'm gonna get drunk, stoned, and laid. However, I obviously can't do this before 11 pm. So I am going with my date to my friend's beach house. my parents are mad helicopter parent so this whole plan needs to b air tight from start to finish. At 6 pm my date and I will be picked up by a limousine. In this vehicle ther will be 6 other couples. Only 3 (possibly 4) will be accompanying my date and I to this beach house. If I say that I am sleeping over than my parents will drive over to find me. If I don't notify them they will flip a ****. HELP! If there are any further clarifications feel free to email me at gentoo101@yahoo.com