The Last American Virgin (1982)

Gary, Rick and David are American teens with one thing on their mind. They move from party to party, trying out their latest chat-up lines, which usually ends in miserable failure for Gary, as he's more interested in finding true romance than a quick fumble in someone's parents' bedroom. So when Karen arrives at their school, Gary falls head over heels in love, but Rick's baser intentions towards her threaten to break up their friendship for good.