I'll have to agree with Crispy that it's more fun to "beat it up" than to "eat it up"...even with my weak back I still manage to give 'em a good pounding now and then.
But it's also nice to go down on a sexy young girl who really turns me on.
I love it when they love it... but also just the experience of a pretty, sweet, young pussy in my face is awesome. I like to finger her G spot area while sucking and licking her clit...and this usually does the trick. And the view of a fine ass in my face during 69 is very stimulating!
Now I don't DATY on all the providers I see, but I wish that more of my favorite providers were into it; there's been several really hot girls in SA who don't allow it at all, and others who really didn't seem to enjoy it.