In reality, I don't care. I'm pretty comfortable with myself and I don't think my dick size has ever caused me any hardship. In terms of fantasy, though, it would be most humiliating/exciting for my wife's friends to know, since I see them all the time. Like if she took a picture of it one day on her phone and forwarded it to her friends, and they all giggled whenever they saw me, that would be hot. Oh, my sister-in-law too, I'd hate/love it if she knew.
I guess what I'm saying is, if the above things actually did happen, it would technically be embarrassing- but any true humiliation would be canceled out by the excitement. I guess at least some of you here can relate?