Good memory. Yes, that was me. The Reader's Digest version is that 2 couples I know went on vacation together. On a drunken/stoned impulse, they decided to swap. The one dude played football for MSU and is a big dude, apparently in all respects. They shared a hotel room (this was back when they were young and poor). The one guy (not the athlete) finishes quickly. He and the other dude's wife sit and watch while the Spartan jackhammers his wife for the next 20 minutes - switching positions, grunting, etc.
The moral of the story is to never, under any circumstances, finish first when you wife-swap. The ancillary moral is to never, under any circumstances, let anyone else fuck your wife. The fucked up thing is that the couple is still together but every time we see them, that's all we talk about. They will forever be tied to that story.