I'll start out by saying that I'm still a virgin so feel free to take what I say with a grain of salt.

I have purchased condoms in the past like how most people do (at convenience stores) and found that most condoms felt pretty loose for me. I'm pretty average in length, being at 5.6" NBPEL. Girth wise, at my thickest I am 4.5" but mid shaft, it goes down to 4.2-4.3". Anyways, I've learned a while back that condoms are mainly categories based on girth and after lots of trial and error, I found that if I wanted condoms that didn't roll up at all, it would be best to select based on my mid shaft girth. The best condoms that fit me are between 49 mm and 52 mm. The 49 mm one's I've tried are: MyONE snug and classic snug, lifestyle snug fit, Atlas true fit, iron grip, and beyond seven. The only 52 mm I was able to try were the Durex Invisible (I think the kimono ones full under this too but haven't tried them yet).

Just above that, would be the Skyn Elite at 53 mm which I may be able to get away with in a pinch but if I was able to choose, I would get the Durex Invisible over these as I've noticed these rolled up a bit on my mid shaft. The majority of other regular condoms that I've tried (Durex air, Trojan Enz, lifestyle regular) are typically 54 mm but for those, the rolling up becomes more noticeable and some slipped off with enough pre-cum.

While I don't think I'll be using these any time soon due to my confidence essentially being nonexistent (constant rejection, being made fun of in the past, and size insecurities, etc), at least I know that snug condoms fit me best. Yay... Again, MY decision on snug was mainly based on it fitting nicely all around. This was mainly about me sharing my trial and errors. Anyways, I hope this was able to help someone who was also struggling with sizes.