As a guy with some decent size, yes it does matter, but it’s a bit different than what you’d think. Sure, all condoms can physically stretch a lot, but when condoms are too small for me, they are too tight and it makes keeping an erection very difficult if not impossible (which kind of defeats the purpose of having them)
I would like to add that a condom not fitting is not a valid reason for a guy to pressure you into letting him not use one (that’s a disgusting thing some guys do), but it does mean that if a condoms doesn’t fit, sex (penetrative at least) is off the table unless either of you can find ones that’ll fit
Yea I’m a woman but I’ve had condoms fall off inside of me and it’s not fun so I’ll speak on it lol. As #3 said most of em stretch more than enough but there’s certain cases even a magnum has not fit certain partners of mine. It fits length wise but they always got super red lines around the base of their dick where the rubber rolls. like when a girl wears a hair tie too tight on her wrist it literally cut off the blood circulation.
And then when their dicks are a lil on the skinnier side, a magnum will fall right off inside of me bc they’re not thick enough to keep it on with all that movement. So I gotta switch to a classic, Trojan or skyn, most any brand will do as long as it doesn’t say “large” condoms anywhere