If you listen carefully at 2.37, you can hear a man laughing. That's the director, Anthony Spinelli, who was laughing so hard he had tears in his eyes during this scene (and others). John was in perfect form and he could be funnier than hell playing up a sex scene. Sharon was great, too.
This was the movie that made John a superstar. I recall telling Spinelli that 'this guy should be in prime time, not in fringe porn'. Spinelli shhhh'd me. If there was anyone who could have made it in mainstream television and movies, John was the guy. But John was John, and he loved what he did, as well as the freedom it afforded him to paint, draw, sing, play harmonica, golf, etc.
Rip, dear friend.