I don’t remember how much sex there was in Friday The 13th because any 80s movie set at a camp blurs together for me.

The couple that gets killed in the 1958 sequence at the beginning were in the midst of foreplay, but with their clothes still on, when she comes in and kills them. Kevin Bacon and his squeeze get a real sex scene before getting killed. But multiple kids who don’t have sex get killed, and the one survivor was part of the strip monopoly game.