I think you might be on to something here, though. Just imagine if someone did a gay porn spoof of Chariots of Fire!

Anyway, they only thing I can come up with that even remotely fits your description is a scene from one of the Best of Colt comps.

Two guys were working out in a gym during the begining of the scene. One was lifting weights, and the other was jumping rope. He wasn't naked, but his shorts were so short that his entire cock and balls were hanging out of his shorts (and flopping around quite a bit while he jumped the rope).

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