>>48560193You're just acting prudish which makes you come off as sheltered is all. The vast majority of people have the occasional cheeky wank to someone they know, whether that be teenagers getting off to classmates or older people having fantasies about a colleague, female friend, cousin etc..
It might seem unusual to you given it doesn't come up in polite conversation unless you're around people who're particularly open about their sexuality like I am, but it's definitely a common thing.