Seems to me this was an R rated teen sex comedy that they couldn't get released so they added three hard-core sex scenes that had nothing to do with the plot and sent it out. It's funny, and the sex is hot, but it is kind of an oddity.
Hate to disagree with a previous user, but I thought the soundtrack was just hilarious. Very much like a '50s slapstick comedy. This one's a lot more laughable than erotic and is going right into my saved file. Thanks for the upload!