Some people are riduculously overprotective, even of themselves. If you don't expose, when you actually do, you will get more sick than if you have. Besides, you can find trichomoniasis even on your toothbrush. Read.
BTW, sexy as hell!! Would love to take part.
RE: 'gross': apparently there are ways to clean it effectively before assplay. I know a woman in another part of the US who is very active in swinging / hookup app circles, and she does this, so that selected men can tongue her butt. I've also read similar. Ass licking sure looks cool, regardless.