There are two rules that anyone having anal sex has hopefully heard before: First, always use lube; second, don't go straight from anal sex to vaginal sex. But if you're someone with a vagina who is having anal sex, then there's a good chance that sometimes you have anal sex and vaginal sex in one sexual encounter, so it's important to understand exactly why this second rule exists and how to make it work for you.
If you need a brief health class recap, your anus is technically the end of your digestive tract, and it's where your bowels exit your body. So, any bacteria that's found in your stool or that's been inside of your gastrointestinal tract — your esophagus, stomach, and intestines — can end up in your anus. While it's normal and cool for this bacteria to be found in the anus, it can be a problem if it ends up elsewhere, like inside your vagina.
If you had a penis, object, or finger inside of your anus, and then directly put that same thing inside of your vagina, that can greatly increase your risk of several different infections, says Donnica Moore, MD, a women's health expert in Chester, NJ. "The types of infections it can cause include, but are not limited to, bacterial vaginosis, yeast infection, UTI, or complications of all of those things," Dr. Moore says. "It's along the same lines of why we teach people to wipe from front to back, not back to front, after you use the toilet." But this isn't meant to scare you into avoiding anal sex entirely; it's just to motivate you to take the proper precautions if you're going to do it.
To guard against contracting some kind of infection, thoroughly wash the penis, object, or finger that was inside your anus with mild soap and water before it enters your vagina, explains Dr. Moore. Or, you can use baby wipes or moist towelettes to clean the penis or object, she says. If you're using condoms, you still have to use these clean-up measures, and you also have to put on a fresh condom. (Often, condoms don't cover an entire penis or penetrative object, so there's still a chance that it could have bacteria lingering on it.)
While these measures might seem a little bit extra, or at the very least a mood-killer, there are a few ways that you can make the transition a little less awkward. You could always use something else for vaginal stimulation after anal sex, like a dildo, vibrator, or your hand, Dr. Moore says. Or, you could just have vaginal sex before anal, or opt for shower sex (so you don't have to worry about going to the bathroom to wash off before having vaginal sex), she says.
Now, if it's too late and you already had anal sex and then vaginal sex right afterwards, you should urinate immediately after, Dr. Moore says. Also keep an eye out for symptoms of an infection, including fever, chills, discharge, pain or itching, blood in your urine, or any rectal symptoms, and call your doctor if you notice them. "And frankly, if you have those symptoms anyway you should call your doctor," she says.
All of this might sound like just another chore that you have to think about during anal sex, but it's one surefire way to ensure you're having safer sex. And hey, if this means you only end up having anal sex one day, that's not the end of the world, either.