But what is everyone else in your family does it? Then you'd feel like a right idiot.
They don't, I know them too well for them to do it.
Unless you watch them in the shower you don't know if they are fapping, pissing, having sex with each other, committing murder, or even participating in an occult ritual with their monthly-meet of chicken-fucking satanists. Seriously. Don't spit shit that you know what someone does in the shower ALONE on the premise that you "know them too well". You never know a person as well as you think you do.
I don't need to watch any of them, family is family, you fucking grow up with them. You pretty much know what they do and don't do. Don't give me this BS.