As Paul Thomas Anderson has said many times, seeing Dirk Diggler’s enormous penis in Boogie Nights is like seeing the shark in Jaws: it’s more powerful if you have to wait for it.

We now know exactly how the crucial prosthesis was constructed due to Grantland’s 16,000-word oral history of Boogie Nights.

The figure was composed of plaster, with a pubic merkin manufactured specifically to match Mark Wahlberg’s hair color. (A customized bulge for his pants was also built by the crew, which was described as “a woman’s stocking knee filled with birdseed.”)

The final penis was a bit smaller than Diggler’s oft-mentioned 13 inches after the team tested some prototypes: “We sculpted a version that was 12 inches long, and we tested it, and it was just way too big,” special-makeup-effects coordinator Howard Berger told Grantland. “It looked like a weird monster penis.”

The version seen at the end of the movie was seven somewhat tumescent inches long: “It was the size of John Holmes’ penis, but Mark is like eight or nine inches shorter than John Holmes,” said editor Dylan Tichenor.

Mark Wahlberg Discusses ‘Boogie Nights’ Prosthetic Penis

DEC 12. 2014

Mark Wahlberg took a naughty souvenir from the set of Boogie Nights.

The 43-year-old The Gambler actor spoke on Late Night with Seth Meyers the night before, discussing what it was like to film Boogie Nights while wearing a prosthetic penis.

Wahlberg was more than ready to talk about it, describing how uncomfortable it was to have to wear it all day on set. (He wasn’t even able to use the restroom!) He also claims that it was the only prop he retained throughout his entire career, and that if you’re lucky, he might auction it off eventually.

‘I didn’t think there would be that much interest in it but maybe I can at some point sell it at auction for charity.’

Mark also discussed the process of creating the prosthesis.

“I have to stand there and take off my clothes and the start sculpting this thing around you. It’s very uncomfortable and very awkward. And the first time they did it they did the exact same specs, measurements, to what they thought John Holmes was like – for anybody who doesn’t know who John Holmes is, he’s a very famous porn star in the 70s – so this thing was like down past my knee. You’d sit down and the thing would bounce up. So the first one did not work, everybody thought it was ridiculous,” Mark said. “I had to come out to set and show everybody, and I’m like, ‘Oh my God.’ Everybody’s, ‘Hey! Look at this thing! Come check this out, what do you think?’ Then they had to modify it a little bit, it was pretty embarrassing.”

Wahlberg reveals, “I used to keep it in my desk drawer. And I’d take it out and slap my friends in the face with it. I don’t keep many things from my movies, but that just seemed to have personal significance.”