Parents Guide for
Secret Admirer (1985) More at IMDbPro »

Two adult neighbors (not married to each other) park at a makeout place while looking for their teenage kids and get frisky with each other. When she sees her husband in the next car kissing the neighbor's wife, she dives down and puts her head in the guy's lap. He says his wife rarely does 'that' anymore and thinks she's about to perform oral sex on him when she points out that their spouses are in the next car.

Kelly Preston's breasts are shown for a few seconds in C. Thomas Howell's car during the makeout scene

During a party, a teenage couple go into the parents' bedroom to have their first sexual encounter with each other. They are seen in bed, without nudity, trying to figure out what to do and we hear the girl say, "You're not doing it right" before she finally gives up in frustration.

She turns sideways to pull the covers over her breasts. After she says she doesn't want her friends to know she didn't do it, she throws the covers back. Her breasts bobble around as she gets out of bed and she is seen from the rear pulling up her panties.