Johnny Henderson, 23, from Penrith in Cumbria, had been downing drinks with friends when he promised that he would have the phallic shape burned into his behind.
He said: 'It was my idea. We had a few drinks and we got a bit giddy. I don't know why I thought of it. I come up with stupid stuff all the time.'
Neighbour Derek Weir, 41, caught the spectacle on camera and shared it on Facebook.
The clip shows the coat hanger, bent into the shape of a penis, being heated in an open fire until it is glowing red hot.
As it is branded onto Johnny's behind a plume of smoke comes off his burning buttocks, sending him fleeing while shrieking in agony and leaving a penis-shaped scar on his bottom.
Mr Henderson said: 'I'm a big fan of Jackass. I like to get reactions out of people. The only person that might have been shocked is my other half but she knows it's something that I would do.
'It still hurts now but I don't regret it. My sister calls me an idiot but I don't mind.
'Everyone laughed at it, even my boss laughed at it and called me a legend.'
His wife of four years Rowena, 23, only found out about his antics when she came across the wince-inducing footage online.
Mrs Henderson said: 'I was a bit shocked. I was a bit miffed that he had done this without thinking and that he thinks this is normal.