Help please !!!

Hi, I've been searching a movie for a long time, here's the description of a scene I posted in "I Need To Know" boards on iMDB(with no success yet).
I watched The Salton Sea a long time back, don't remember if that is it.

There was this movie i saw, it's from 2000-2010s. It's kind of an upbeat movie about drugs and stuff, something like "Spun". I could only remember a scene where a junkie takes the lead guy to someone to buy coke from. He warns the hero to not eat or drink anything at the dealer's as he is a really weird guy. If he does, then he might wake up next morning with his sh*t smeared on his face.

That's exactly what he says. So they reach there at the dealer's(who was apparently gay) and he sees 2 guys there just lying there, totally zoned out.

So it goes well and they manage to score drugs. That's all i can remember.

The original post: http://www.imdb.com/board/bd0000001/flat/200400425?d=200400425#2004004 25

Will be really great if someone here can help me. It's a fairly known movie, I'm sure. Thanks :)

IMDb ain't got *beep* on me !!