Susie replies:

People with vaginas do not always bleed during or after sex.

But when they do bleed during or after sex and it's not because of menses, then it's due to some injury in the vagina or vulva. As well, some sexually transmitted infections -- Chlamydia is a biggie for this -- can cause bleeding with or after intercourse or other kinds of sex.

The vagina and vulva are delicate, yet resilient structure made of skin, mucous membranes, muscle and so forth. The lining of the vagina is very similar to the tissue that lines the inside of your mouth. It's soft, squooshy, and it bleeds when it's cut or roughly rubbed. During sex, the vaginal lining can get scratched or torn, particulatly when a person isn't very aroused and lubricated or using an extra lubricant as needed. As such, it can bleed. That's why some people bleed during sex -- not just vaginal intercourse either.

Manual sex or penetration with toys can cause similar abrasion. Then there's the hymen, or vaginal corona. While most people don't have much vaginal corona left by the time they have sex, the vaginal corona can get scratched or torn during manual sex. This can also cause bleeding. And in especially traumatic or rough sex, people might end up with abrasions and cuts around other parts of the genitals, like the labia, perineum and anus. Likewise, all these parts can bleed when cut, too. All these cuts and abrasions? They're simply injuries.

How do you avoid injuries during sex? Do it gently and at a comfortable pace. If anything hurts, stop and readjust till it's comfortable. Use extra water-based lubricant; lube protects the genitals, and it lessens the risk of condom rupture.

And if you or your partner continue to have bleeding despite taking precautions like only entering the vagina during high arousal and using lubricant, you or she will want to check in with a sexual healthcare provider to find out what's going on.