The very first thought that sprung to my mind was, of course, its sexual context. Here I wouldn't use the word in question in reference to males. (Maybe if they have exceptional lips....I think I've said too much, far too much.)someone or something which is excellent or very pleasing
I have never heard the word "peach" used in any sexual context. I can't think it is that common, not in BE anyway.
peach - nice ass pussy(vagina); A nicely shaped, and usually freshly shaved vulva, typically characterized by large labia majora (outer lips) and small, if not invisible, labia minora (inner lips).
[I will be careful not to say it in Polish, though, now that I have been warned.]