What actually happens if you don't pee after sex

• INSIDER spoke to an expert to see whether or not you should pee after sex.
• If you have a vagina, urinating after sex can reduce your risk of getting a urinary tract infection.
• You don't have to pee immediately after you're done having sex.
• If you get recurrent UTIs and are in an established relationship you should make sure you and your partner aren't passing the infection back and forth.  

If you have a vagina you've probably heard many times that you should always pee after sex. But given that running to the bathroom isn't necessarily what you want to do after a hookup, you've probably wondered why you should even bother.

We spoke to a Dr. Frederick Naftolin, a professor of obstetrics and gynecology and co-director of interdisciplinary grogram in menopause medicine at New York University to get to the bottom of what happens if you don't pee after sex.

People with a vagina should urinate after sex to reduce the risk of getting an infection.

People with a vagina have a higher risk of getting an infection because of its proximity to the urethra and the anus. In this case, the urethra is shorter compared to that of someone with a penis, making it a lot easier for bacteria to get from the anus to the urethra and then to the bladder.

According to Dr. Naftolin, sex increases the likelihood of this happening because "when people have intercourse or even foreplay, the rubbing around the urethra inflamed it and it begins to secrete lubricants and fluids as a response-and those fluids then are good conduits for the bacteria to get up there."

Because of the ease with which people with a vagina can get infections, it's especially important that they pee after sex so any bacteria can get flushed out before it can get into the bladder.

Not peeing after sex can lead to a UTI.

The most commonly known infection that can be avoided by peeing after sex is a Urinary Tract Infection (UTI).

UTIs are caused when E.-coli are moved from the rectum to the bladder via the urethra. The urine in the bladder is sterile so the "bladder doesn't have very much defenses against [bacteria]," explained Dr. Naftolin.

As a result, you may experience frequent and painful urination. The best way to try to avoid this discomfort is to flush everything out post-sex before it can reach the bladder and wreak havoc.

It's a good idea to urinate after sex that isn't between a penis and vagina too.

Because of the anatomy of a person with a vagina, in other words, their short urethra, it's important for them to pee after sex even when they haven't had penis in vagina sex.

"The same rules apply if two women are having either vaginal sex or oral sex, then those areas are exposed in the same way," said Dr.Naftolin.  

People who have a penis are also not completely immune from infection.

As Dr. Naftolin explained to INSIDER, it is possible for those people to get a prostate infection that feels similar to a UTI through penis to rectum sex, during which the penis is in constant close contact with the anus. In this case, he would advise to evacuate the rectum before sex and wear a condom during to avoid infection.