In which the protagonist commits rape by fraud, dressing up in a costume of Betty's boyfriend, then having sex with her under false pretenses? Probably not the best movie to shine as a star of anything good sexually. (The peeping tom crap too)
It's my interpretation that the protagonist in question provides oral sex to the lady and stimulated her clitoris in ways her jock boyfriend never thought or knew how to. It's my understanding she definitely enjoyed that. It is also my understanding that she was not too pleased to find out who was behind the mask at first.
It's further my understanding that Revenge of the Nerds II: Nerds in Paradise (1987) [1] intimates that they then became something of an "item" (in today's terms that means they dated!).
Finally, it's my understanding that it's a fun movie and not a manual for life.
Her reaction and enjoyment at a later time is immaterial: It's rape (or sexual assault, depending on jurisdiction) to have sex this way.
Rape and sexual assault are something you can pick out before you engage in them.
>it's a fun movie and not a manual for life.
It certainly can be a fun movie and have misguided lessons for people. Many old pieces of art do this, but are still enjoyable in other places. That said, the bad parts should still be pointed out clearly as bad, even if it taints enjoyable experiences of our youth. They aren't harmless. They normalize this crap and convince young fools this type of thing is fun instead of criminal.