One Size Fits All (1984)

The gym is both a new world and a new job for young Brian — and a revelation. The first day on the job finds Brian increasingly turned on by all the muscular hunks pumping iron in the weight rooms. Although he is told by the security guard that he must be out of the building before it is locked up for the night, Brian falls asleep after his long day. He begins to dream about all the jocks he observed during the day and the dream becomes a full-blown orgy!