I enjoy having my asshole probed with a tongue, or a cock, or a finger, or whatever my partner wishes to probe it with. Isn't licking the asshole a part of doing oral? I mean while you're down there enjoy it all.
I love being airtight with cocks in all my holes but occasionally I will be made airtight with tongues in all my holes instead. It really feels nice having a tongue up my ass while another tongue is up my pussy or working my clit.
So yes lick away wherever you want. I love it all from head to toe.