According to the Urban Dictionary it means placing your tongue in the ass and probing all around the circumference of it while helping them masturbate.
I love to lick my wife's asshole. She would never admit it, but she loves it too. She would never ask for it, but she's more than happy to spread her cheeks and let me in while I'm down there. It drives her wild when I poke my tongue in and fuck her with it.