This should be pretty easy. I think I first read about it and saw a youtube clip here. An 80s slasher movie where one of the hunky male leads strips down to his tightie-whities and does a Flashdances/Footloose dance around an empty barn while his girlfriend or the female leads watch through a hole in the wall. Maybe he takes a shower as well? It was a pretty elaborate, choreographed scene that went on awhile. Definitely an unusual role reversal for an 80s teen (horror) movie. I only saw the dance clip that was linked so I don't know if he ends up getting killed after the dancing is over. I thought it might be "Girls Nite Out" but there was no scene like that shown in the trailer. I want to say all the characters (male and female) were on some kind of athletic team together?