Fitting Underwear: Help! My bum is eating my undies!

7/16/2019

Next up in my panty fitting series is probably the most common problem I see; the back of the panty sliding into the bum and causing much discomfort. In American English we call it a wedgie. What causes it and how do we fix it? Let's take a look.

Problem: The back of the panty is sliding into my bum

Symptoms:

Bunched up fabric at the back gusset seam. Not enough coverage over the bum cheeks.

Solution:

There are three things that can cause the dreaded wedgie, so let's begin with the simplest.

Check your size. Did you choose the size that best corresponded to your current measurements? Did you blend between sizes, if necessary? If the panty is too small, there won't be enough fabric to cover the back. Check your measurements again, because it's easy to assume that they haven't changed since your last project.
When finishing the leg opening, did you stretch the elastic or fabric band? There needs to be some resistance to hold the fabric firmly against the body, and if the leg opening is loose the fabric is free to slide around wherever it pleases. If you don't wish to have a firm leg opening, at least stretch your elastic or band from the back gusset seam up several inches into the bum curve so that it will cup the bum cheeks.
If you have chosen the correct size and you did stretch your elastic/band, then you may simply have a different bum shape than the pattern was drafted for. Nothing wrong with that, and the pattern alteration is simple. I don't have a very scientific method for deciding how much will need to add to the pattern, so it will be a bit of trial and error.

Pattern alterations:

Beginning from the back gusset seam, move up about 2-3" and 1/2" out from the bum curve. Draw in a new bum curve and blend back into the original gusset seam and side seam. This is just an approximation to give you a place to start; you may need more or less added to the back.

Also, if gravity or weight loss has caused the fullness of your bum to lower, you may need to also lower the widest point of the bum curve.

That's it for today, happy sewing!

3 Comments

Charlotte

4/12/2021 03:26:09 am

Hello! Thank you for your fitting tutorials for pants, they are very helpful.
I am new to sewing underpants and have found that I need to move the gusset so it is higher at the front. My problem now is where should the gusset end at the back? Do you have a tutorial for this?
Many thanks

Cassie

4/12/2021 01:53:52 pm

Hello! You are welcome. I design my patterns to have the gusset longer in the front for this very reason. The back (in my humble opinion) isn't as important. So the answer would be, whatever is most comfortable for you.

Jane

12/12/2022 08:21:47 pm

I often wear a shapewear thong and it's always tight up between my bum giving me quiet a wedgie but I've got used to the feeling of having them up my bum all the time, I wear a high waisted shapewear thong that's quiet comfortable to wear all day. I guess you get used to anything given time.