Porky’s 3: Porky’s Revenge
With no more story to tell other than an excuse to get the usual gang back up on the screen, the movie uses the device of Porky - owner of the underground brothel -plotting revenge against the horny cast.
Apparently (and I read this online) he wants them to throw a big basketball game because he's bet on the opposing team. All I remember is a vague few jokes and the delectable Swedish exchange student falling for the joke of flashing when they step up to the graduation podium and opening her robe to reveal all.