Let’s get this out of the way: Unless it’s relevant to the plot, I’m not going to address prophylactics and birth control. In real life, I have a pregnancy phobia (of me being pregnant, not of pregnancy in general) and a general fear of STDs. Nothing turns me off faster when I’m writing than being in the middle of a fantasy sex scene and suddenly worrying about my female character’s pregnancy, or worrying about that one night stand’s STD status.
In my opinion, I deal with enough sexual fear in real life to let it bleed into my fantasy world. There are lots of ways in which sex can be dangerous and exciting, such as sex with a stranger, sex with BDSM elements, sex on a cliff, etc. But STDs and pregnancy scares aren’t exciting. They’re just scary to me. In the erotica world, I don’t have to justify the lack of birth control or prophylactics, nor do I have to justify my characters riding bareback. In mainstream, I do, but I shouldn’t have to here.
Of all the places in the world, I shouldn’t have to fear sex here. Erotica is where sex, even dangerous sex, is safe. It may throw some people off not to include those concerns, but I just can’t do it. It’s not that I’m unaware of reality; I’m hyperaware of it, which probably accounts for a good deal of my celibacy.