From Hugh (via email) "I came across an old Sean Cody clip where the guys get sucked off, but there's a really brief shot of the girl they're watching to get hard. I've seen scenes where there's a laptop or TV playing straight porn, but this is the first time I've seen an actual girl masturbating in the background, which makes me wonder how prevalent a practice it is, esp. with studios that already have girls on the roster."
If you look at the first screen capture below, you will notice the two guys were looking on the right instead of the guys sucking their cocks.
The reason? The two were looking at the naked woman.
The scene was released last Oct 30, 2002 where it mentioned in the description "We got a pretty girl to strip down, sit off camera, and masturbate to give the guys inspiration. You can't really see her, but that's who the boys are looking at."