An infection is no fun. This is the way I love to do the vagina/anus anal play:
While giveing some fun to womans I do prefer to slowly work down with kisses. First I kiss her lips, then slowly work down to her boobs. The best part there is when I do have a 3day beard and work down her neck most women get tickeled.
From the boobs I slowly work my way down aside her belly button and slowly reach her venus hill. I move more and more down but do not go for her clitoris. First I play with her labia with my tounge. After than I cicrle around her clitoris and start to stimulate it.
I love to lick there and watch over her stomach going up and down while she is getting turned on more and more. I like to feel her clithoris getting biger while her blood rushes there. Its great to feel it with the thounge. Sometimes I wait until she nearly finishes to push her into the right mood.
If she reacts good and gets turned on like hell her vagina starts to produce her sweet juice. I start slowly lick down over her perineum area. I lick and kiss around her buttcheeks and start to slowly involve her anus.
There I do enjoy to feel her pulsateing anus with my thounge. From there a lot of possibilities are open for the next stage of play.
That way it is safe and makes a lot of fun. No bad bacteria in her vagina and a lot of fun.
Sometimes I nearly finish myself just be pleasureing a woman that way. The more the woman gets turned on the more I get turned on as well.