When Atlanta metal men Mastodon first met their heroes in Metallica, guitarist Bill Kelliher decided to make a lasting impression on drummer Lars Ulrich that might have ended their friendship before it started. While in our studios for an Interface taping, bassist Troy Sanders tells Spinner how Kelliher exposed himself to Ulrich at their first gig together.

The incident -- which Sanders swears is true -- occurred at a 2007 gig in Portugal. "The show was over and they had their 15, 20 minutes of quiet, band time," Sanders says, sitting next to Kelliher. "And then they come out of their trailers and Bill walks right up to Lars Ulrich, and puts his penis in Lars' pocket. I'm not kidding. I was like, 'Dude you're about to get your a-- kicked by a security guard.' That's what makes Bill so special. That, and his mustache."

"I have a picture of him kissing me on the cheek," Kelliher says. "He must have liked it."

Luckily for Mastodon, Metallica are apparently still fine with the incident -- the bands are set to tour Europe again this summer. And, don't miss pics of Mastodon's many tattoos on Noisecreep.com.