It’s so bad that my fiancée has some bras that say she’s a B cup and others that says she’s a D cup. In order to go bra shopping, you have to actually try them on to find out if they fit.
If I had to try on underwear to see if they fit, I might not bother with underwear at all!
Good thing guy underwear doesn’t give one fuck about the shape of the penis. They either mush it into the crutch to defeature the shlong, or they let the whole thing just flap around under loose shorts.