Barbara Crampton and Kathleen Kinmont appeared together for all their screen time which was about ten minutes, five of which took place when they were in bikinis, topless, completely naked or briefly showing off their buttocks for the mooning scene. In fact most of their dialogue took place when they were in their bikinis, topless and then completely naked.
Fraternity Vacation was the first movie in which Kathleen Kinmont appeared nude. Perhaps as a bit of handholding it was agreed that Kathleen Kinmont would take off Barbara Crampton's bikini first, as Barbara Crampton had done nude scenes before, and then the now topless Barbara Crampton would take off Kathleen Kinmont's bikini.
In contrast to Kathleen Kinmont giving Cameron Dye a full-on kiss, Tim Robbins and Barbara Crampton avoided kissing each other on the lips before Barbara Crampton as Chrissie asked Kathleen Kinmont as Marianne to take off her bikini.
Chrissie makes a couple of comments on the amount of furniture in the condo and each reflects the amount she and Marianne were wearing. When Chrissie says there was no furniture the girls were in their bikinis and when she noted that there was furniture later on towards the end of the movie, the girls were fully covered up.
In 2001 Australian men's magazine People looked at Kathleen Kinmont's nude history and concluded with her first nude work in Fraternity Vacation: "Kathleen started in fine form at the age of 20 with a nude scene in 1985's Fraternity Vacation. Both she and Barbara Crampton (later in The Bold and the Beautiful) peel off their bikinis in a STEREO STRIPTEASE (sic). Honestly, you don't know where to look. Best REWIND (sic) and watch 'em ONE AT A TIME (sic)."
Not Another Happy Ending (2013) has a nude scene that was set up in similar circumstances to Fraternity Vacation. In both instances the women perform the nude scene from a suggestion made by their respective boyfriends. Ironically the beneficiaries of these nude scenes are not the boyfriends but the boyfriends' rivals.
Chrissie and Marianne were the girlfriends of J.C. and Chas and they played a joke on Mother and Joe, the rivals of J.C. and Chas when they stripped naked in front of them. However the joke was really on J.C. and Chas as Mother and Joe were the only characters in the movie to see Chrissie and Marianne naked not J.C. and Chas.
Four women have shown their breasts here Barbara Crampton, Kathleen Kinmont, Roberta Whitewood (Sheree J Wilson's body double) and Penny Mathews. Of these four Barbara Crampton and Kathleen Kathleen shown their breasts for the longest time.
Roger Ebert in his review of the movie said that due to the Barbara Crampton-Kathleen Kinmont nude scene their characters were treated as hookers. Barbara Crampton herself later played a hooker in The Godson but ironically kept her clothes on in that movie.