Please help me with comfortable knickers

[Plusplug]

I have worn M&S full knickers size 18 since I had my DDs - I loved them and they were always comfortable. Then I lost weight and bought the same in a smaller size 12- I constantly have an uncomfortable knicker-up-the-bum situation and it's genuinely getting me down. I went up sizes - even all the way back up to a size 18. Nothing is right anymore.

People on here always recommend M&S full briefs, so is my bum just deformed or misshapen after weight loss? It looks normal-ish to the untrained eye. The gussets (shiver, hate that word) just seem so narrow 😩. I teach all day and cannot be constantly waiting to rearrange my underwear!

Please recommend me something reasonably priced which might help!

Sloggi full briefs not cheap but the best.

sainsburys pants are great

I like George full briefs too, good quality cotton. I buy a large size, then give them a hot wash and tumble dry. The fabric is mainly cotton with some Lycra and is nice and soft, without over-tight elastic.

I'm having similar prob with M&S knickers, I bought size16 but they shrunk in the dryer (especially the lace top) so bought size 18 exactly the same knicker expecting them to fit after going in the dryer, they haven't shrunk🤔

I hated Wirarpa pants. Really thick cotton, like old school pants that never wore out.

Another vote for Bonprix. These are soooo comfy!
https://www.bonprix.co.uk/products/pack-of-5-full-briefs/_/A-938748_10?PFM_rsn=browse&PFM_ref=true&PFM_psp=own&PFM_pge=1&PFM_lpn=4
And good value too!