Even if he doesn't understand it, J likes the sounds Mitch makes when he touches back. He likes the way the boy tenses and moves. He's never caused reactions like this in a person before. He's never had this kind of control...in this way. It's interesting. It's worth continuing just for the sake of experimentation.

He's not connected to it --not involved more than by physical contact-- until the tip of the knife digs in. J cries out in shock, pain, and adoring gratitude. It's going to be such a mess when they're done...if he lives to see it. Every movement of that sliced arm seems to make the pain in the muscle fresh and new. There's a stunted pause in his strokes and his hand tightens intensely, then relaxes with some effort.
"..Ahh..not so...so...oh god."
He just laughs nervously, not seeing the point in telling Mitch he's at risk of cutting too deep.

J now has his focus split between the searing pain that throbs with his heartbeat and movements and the rising heat and pressure of approaching orgasm. J tries to regain his matched pace with Mitch and tilts his head back, gasping for air. He feels sure he could stop breathing at any moment.