Yumm, as long as a guy is clean I love rimming more than most things... and can do so for a very long time. I get a lot of compliments on the things my tongue can do... and how long it can do them for... I think sometimes guys feel bad for letting me do it for so long but I'm always like, "You don't understand! I can do this FOREVER!"
It's important to get your Hepatitis vaccines (in general) and clean that area and also inside that area very thoroughly prior (doing a water-only enema once or twice a few hours prior if you plan to play DEEP) to such activities, but IMO eating ass is the creme de la creme of unconventional sexuality.