Anal to Vaginal Sex: What is This Lump?

Author: Aunt Vadge
Qualified Naturopath | BHSc(N)

Last reviewed: November 14, 2025

Hey Aunt Vadge,

I have a strange lump after me and my partner were having anal sex, then went to vaginal sex. What is the lump and what should I do?

Sincerely,
PW
California, USA

______________

Dear PW,

That sounds uncomfortable! First off, let’s address the elephant in the room: switching from the back door to the front without a proper clean-up in between can lead to uninvited guests: bacteria hitching a ride from your bottom to your vagina. Double-dipping is a big no-no!

This switching from anus to vagina can introduce unwanted bacteria and cause vaginal infections like aerobic vaginitis (AV) and other issues. It’s important you never allow this to happen again without a shower with soap for both partners in between, or a change of condom.

Bacteria from the anal passage is not healthy for the vagina. You’re essentially putting faeces into your vagina.

Your lump could be caused by a few things:

That lump might be a sign of an infection, like bacterial vaginosis (BV), aerobic vaginitis (AV) or a sexually transmitted infection (STI). Unwanted bacteria or pathogens from the anus can bring chaos to your vaginal ecosystem.
You might have a blocked Bartholin’s gland or Skene’s duct. These glands can become blocked and swell up, creating a lump. Infections can cause these blockages.
If bacteria get into these glands or ducts, it can lead to an abscess or cyst formation. Abscesses and cysts can appear as a lump or lump.

What to do now

For now, don’t panic. Keep the area clean with gentle warm water rinses (no scrubbing or harsh soaps), wear loose, breathable underwear, and most importantly, avoid any sexual activity that could aggravate the situation. Be gentle with your body as you move onto the next steps.

This is one of those times where it’s best to visit your doctor as soon as you can to be checked, since if you do have a blocked gland, it’s best dealt with sooner rather than later – it can get pretty uncomfortable after a while. If you need antibiotics for an infection, a doctor or nurse can help quickly.

If you’ve never had a pelvic examination before, here are some tips on what to ask for to make it more comfortable. Take a support person if you want to, you don’t have to do this alone.

In the future, to keep your vagina happy, make sure any journey from anal sex to vaginal sex involve a wash-up or a new condom, and be very strict about this! Your vagina will thank you.

Warmly,
Aunt Vadge