Love this. Hot, of course, and very intimate. I liked this moment especially:

Justin's making sounds against the skin of my back, his breath hot and panting. I try to listen to him breathe, try not to get lost in the fuck, but he won't let me. He moves his hips just like when we were dancing, and I feel everything lock in place again, hard cock on that sweet spot, the smell of him, his mouth kissing me, tasting my skin, my sweat…

Brian trying to maintain some sort of control and failing -- that's what Justin gives him, the ability to let go.

Was the change of tense near the end intentional? It threw me off a little bit.