Is it really that "extreme"? I imagine they clean themselves out really really well. I've definitely seen some ass-to-mouth that was not video edited, but the guys' dicks were coming out looking perfectly clean.
Anyway, I've done ass to mouth a few times when I was really horny. I can think of two times I did it when I wasn't planning on having sex so I hadn't cleaned myself out. Both times I basically got horny enough that I wanted the guy inside me. The first time was with my first black guy and first 9" cock, the guy had a condom to fuck me with but he was going soft so i took it off and let him inside me raw, but he wasn't getting hard again so i went back to sucking. I did notice the dick was pretty dirty (no clumps of shit, but there was definitely ass juice (and what looked like a sesame seed!!) but hard to tell how brown it was on a black dick) but I didn't think about it being gross until afterward (and by then, it wasn't gross so much as hot b/c it was gross). i don't remember there being much of a taste. The second time was with the biggest dick I've had, 10" but HUGELY THICK. Again, I hadn't meant to fuck but seeing such a huge dick, I had to ride it. We switched up positions several times and he didn't have a condom ('cause I invited him over for head) so he was fucking me raw and I went ass-to-mouth and back a few times. He's the only guy who's ever cum inside me; I thought he didn't cum, but he told me almost a year later while chatting online that he came inside me.
I don't know how dangerous it is, but I survived.
I don't hook up with men much, but when I do, it can get pretty hot...
Definitely prefer women, though. Much rather lick a woman to ecstasy and keep her there for as long as she can take it. | 
More importantly I don't think it's sanitary. I wish they would stop that A2M, because many straight men think that's something women LOVE and can't live without. 
