i wonder the same!
that's why I took my wife at a nudist beach . She went topless, i was in underwear Most of the time and nude in the water. It was a very hot experience!
The beach is basically a gay nude beach, so it was all men, and just a few women (included my wife). My dream was Expose her to other men and most of all make her watch other cocks, especially the big ones. And she did.
There was a nice range of size, a lot of decent penis, like mine (I’m little above everage, 6-6,5 inches but i’m a shower so i look very big when i’m soft). But different from all of the other there was a man, not very good looking actually but very, very big. At least 8 inches, maybe more, and totally aware of it: he was standing on the shore, touching his monster, proud of showing himself.
I noticed him and my wife too, everyone actually! So i tried to let her talk about him. She is very shy and never talk about sex but i asked she noticed the man with the monster cock and she admitted.
“He’s very big, isn’t him?”
“Oh yes, he’s very Hung! Never seen one so big, i think it’s too much for a girl”
“How much do you think is bigger than me? ”
“Well, He has such a thing...”
For me, it was so exciting listening my shy e little wife talk this way about another cock. Unfortunately he disappeared and We didn’t meet anymore. I tried to let her talk again about him but couldn’t. She told me watching a big cock is not horny for her, it depends on the man, if he’s hot having a big cock it’s turn on, otherwise is just a freak, a curiosity.