If there's no small talk at the end of a session, I'm inclined to think that it likely didn't go that well. One party is pissed at the other for whatever reason(s). The other kinda knows why the other is pissed and reciprocates the mood. Both gets dressed in silence, and maybe there's a stiff 'goodbye' at the end.
This tends to happen with the BP types who false advertise, give crap service, have a lousy incall, weren't fresh, and you just ignored 2-3 red flags before all this happened. For this, you, the guy, are partially pissed at yourself for blowing off those red flags.
I prefer mine to end with the small talk, maybe a little joking and laughing, a little bit of hugging and smooching, and almost the threat of wanting to go again. A good sign is if you or she may ask, 'How long are you in town?' to maybe set up another visit. You walk down that hall and to your car with a shit-eating grin on your face. You get to your car and be like, DAMN, that was good!!!