It's a really, really sappy thought, but John -- even still moving in Q (although slower) -- can't help the insane thought that crosses his mind. Q is so ridiculously beautiful like this that he'd be willing to forego his own pleasure a great deal of the time just to watch this.
It occurs to him a second later that maybe they should just record it, and he feels better for it. He will not be a sex martyr.
Q with all his shouting and proper kissing and tightening make it completely impossible not to follow along, a few seconds later. John doesn't make nearly as much of a scene, only smashes his lips harder onto Q's and completely fucking blanks out most anything beyond bliss.