If something turns you on enough to give you an erection, that's pretty fucking appropriate. The only kind of erection that's inappropriate is the one you get because people have made you so worried about getting them in public that you can't stop thinking about how imperative it is that you not get one. And that's only the fault of childish insecure people who put that idea in your head. Also, not for nothing, but women totally get clit boners. And cloths hide them well. But if the woman is naked, they're a whole lot more noticeable than anybody likes to admit. Except for me. I love admitting it. I'll probably do it again in a second.
I got a semi- erection while a pretty female junior doctor was giving me a prostate exam. I didnt think she had seen my tiny cock at all soft or at half mast because I was on my side and facing away from her but after the exam and after she had left the room I got dressed and noticed there was a mirror on one of the walls that gave a pretty clear view of the opposite side she was standing. I also got an erection while my girlfriend was confessing to me that she had fucked other guys. I not only got an erection but thought I might cum in my swim trunks when I saw a very sexy female cousin in a bikini.