"How to lick a girl out" post gives some *very* specific tips. Make them feel "like unicorns eating ice cream and galloping around the rings of saturn" - or something. How to eat a woman [or anyone with a vagina, FYI] out.
The way a woman is built, penis sex alone isn't a good way to get most women to orgasm. What are the side effects of sucking a woman’s vagina with your tongue during sex? Of course it's gyongyos.info's an awesome experience licking a gyongyos.info will give her mind-blowing orgasm.
In terms of an HIV positive person licking a woman's vagina and posing a risk to the woman, this is pretty implausible. There have never been.