Don't know about disrespectful but it's a little weird, especially if you know the person.
I feel quite the opposite. For me, fapping to someone you don't know is disrespectful and weird; it's like reducing them to a piece of meat whose only use is to get me off. For that reason, my fantasies are almost exclusively about people I know. It's the woman that attracts me, not the fact that she meets some arbitrary standard of beauty; to me all
of the women I interact with here are beautiful, even if they are a little heavy, small-breasted or don't wear make-up. That doesn't matter to me.
So when @MamaMeadow
writes about her husband going balls deep with his cock into her throat, I put myself in his place, pretending that it's my cock in her gullet. When @Surrender2U
posts about her love for fighting off her attacker until he overpowers her, that becomes part of my fantasy of her. When @KalistaSadi
displays her submissive side, I include that in my fantasies of her and the chatroom tendencies of @angellove
become part of my fantasies of her
; "Oh, fudge, I'm going to get raped!" Likewise knowing @Tragedy
as a friend has made my fantasies about her deeper and more erotic and even with newer members like, for example, @uneasesfairy
my fantasies about her become more detailed and arousing the more I find out about her.
The point is, every one of these women is real and in my fantasies they become more so which makes my fantasy in turn much more incredibly real for me. I know this isn't for everyone; some people might think that having rape fantasies about a friend is a violation and I can understand that. But in a sense, in my case, it's proclaiming my attraction and desire for them, whether they know it or not (and I think each of the ladies above is well-aware of my feelings for them).