Iggy Pop and his large penis.
Punk rock was known for pushing the boundaries purely on the reason that they were there. On stage behaviour included simulated sex, explosive vomiting, nudity, urination, exposure and stage diving.
Iggy Pop was one of a number of punk musicians associated with these antics. It is probably correct to attribute this aspect of the genre to Iggy Pop and on that basis it would pre-date punk.
He was a child of the counter-culture and began his musical career in 1969. He is part of the band The Stooges. His on stage antics is attributed to The Doors concert in 1967 at the University of Michigan. At the height of the punk era Iggy Pop commonly exposed himself on stage . This was his trademark.
Though the first rock musician to pull his dick out on stage is thought to have been Jim Morrison in 1969, circumstantial evidence suggests that Iggy could also be credited with this. Iggy had began his musical career in 1969 at a venue in Manhatten and was soon known to have a big penis. He appears to be the first musician to appear on a record cover showing his cock held by what looks like a male concert goer at an event. In 1973 The Stooges issued an album of songs (Raw power) with Iggy on the cover naked.
Typically Iggy would expose himself completely towards the end of a Stooges concert by pulling down his jeans. He would continue singing. A good example of this is contained in footage of a Stooges concert held in the 1973-4 era. For the record he does have a long penis. Iggy is a born showman. His penis and balls are darkened for emphasis as is apparently his pubic hair. He swings his penis to lengthen and firm it up : there was an element of exhibitionism in his stage behaviour. The footage itself is only 27 seconds, but covers a much longer period of time. There are crowd scenes spliced in, and the camera appears to jump from in the audience to below the stage to the stage and back. There are a series of close-ups of Iggy. Iggy at that time was using cocaine and performed on stage high and this appears to be relevant. Cocaine is a stimulant and causes the user to be extremely euphoric and to lose their inhibitions, which can lead to sexual urges. It doesn't affect everyone that way, but it's quite common.
An interview taken in 2000 refers to an occasion where Iggy pulled out his penis on stage and placed it on an amplifier and getting an erection from the vibrations for all to see. At another concert he pulled a girl from the crowd who gave him a blow job on stage. At another he appeared in ripped jeans with his balls hanging out. At another he stroked his penis as he sang.
The best photograph of his penis is the nude photograph of Iggy at taken in 1971 by Gerard Malanga and used for the 1973 album cover Raw power. He looks like a genuine innocent whose innocence oddly enough is compounded by his large penis.
There is another anecdote of Iggy appearing in a video for the artist Peaches wearing the tightest of pants with his package coming out.
His on stage antics are less today : he may play in see through trousers unzipped so that his pubic hair shows. He usually is bare-chested. Other recent performances have him accompanied by naked men dancing.
Iggy Pop writes sings about his penis in The Stooges album The weirdness issued in 2007. The opening lyrics for the song 'Trollin' features the lyrics: "My dick is turning into a tree". He defended himself in Rolling Stone magazine at the time adamant his penis has a place in his music.
You write about things of importance to you, And its gotta be for real. Do I think about my dick? All the time. I got a right (to think) to sing about it. If I thought, Its time to write a rock song, Id better mention my dick, then I wouldnt even be able to say dick right. But its nature-oriented.
Iggy Pop is particularly popular in Australia and New Zealand as he appeals to the rebellious and inherently anarchist nature of the Australasian psyche.
Lux Interior of The Cramps is more associated with simulated sex on stage. His behaviour in 2003 in a London concert was quite bizarre and ended up in him cutting his trousers open with a broken bottle to expose his penis to the audience. Concerts of punk musicians in eastern Europe have involved members of the audience pissing on stage. In the 1980s The East German heavy metal band Rammstein was known for the lead singer playing high on apparently a mixture of cocaine and beer appearing to take his dick out of his trousers and then pissing into the crowd. It actually was a stage trick using a fake penis.