Yes, I do need reassurance sometimes, though for me I'd rather wait, sometimes a few days, before discussing a session in which I felt uncertain about something (and in the meantime I'll avoid doing that thing which I am uncertain about). Directly after a session I do ask my little one "Did you feel good?" or something simple along those lines, but he's not capable of conversation directly after. I find that my aftercare is simply making sure that he's okay (especially his neck because he has issues with his discs there); once he's peacefully asleep then I'm free to savor the lingering deliciousness and replay the session in my mind.

And then fall asleep myself. I spend a lot of energy during a session; I need to sleep after!

But I can certainly see a Dom needing aftercare, and as Oz said, it would be nice if the sub could provide that service.