Iggy Pop 1980
Pop was touring the album Soldier which had an all star cast of musicians including Glen Matlock, Ivan Kral & David Bowie but I don't believe any of these guys were in the touring band. Matlock had toured with Pop before. It was a good rocking show, I don't recall any details, tho.
Pop was shirtless with his pants about as low as legally possible with the button undone. While crooning at the front of the stage, an arm came up and started pulling down his fly. Pop allowed this for a few seconds & then stopped it. After the show, my late friend Artie informed us in wide eyed amazement, "That was a GUY !".

Iggy explains his Dionysian influences to goonball Tom Snyder: