[karlhein]

Anal is sort of a special variety of sex. It feels good to most men, although it's so tight and naughty that often I can't last as long as usual. If you are young, and Mrs Robinson has any special meaning for you, then you certainly don't last long, particularly if she asks you to "fuck my ass" But, I guarantee that Mrs Robinson is much more likely to enjoy anal than your age appropriate gf.
Some women do it just as a courtesy, something to do that's different. Some women like it, in swinging situations, but only for the new guy. For others it's "one and done", they don't like it and can't get used to it.. Others take some warming up, but then get to like it. For others 's the road to screaming multiorgasms.
It's always interesting.
Some Mrs Robinsons, do anal only with you, it's not part of her usual sex life. It's a different level of cheating on the hubby that isn't paying her enough attention. Others, like it in a group setting. For some of the younger Mrs Robinson's it's pregnancy prevention.
Start slow, unless she is the one asking for it. Warm her butt up with a finger or toy. Ease it into her, and watch her reactions. Be gentle, unless she is an anal queen, it's going to take longer to put it in. It's better if you've already cum once, so you don't pop off before she has a chance to get into it. If you are hung like a horse, forget it unless she asks for it. And, as always, lube, lube, lube.