My two sisters, my brother and I spend a lot of time together naked
Essentially this all started originally because our brother was tired of waiting for 3 sisters to get their morning routine and showers done. One weekend he gathered us to talk about it and he suggested a solution, showering in pairs so it'd be much faster. We weren't too sure but we did try it anyway. Now we're used to it, and being naked with each other is completely normal. It's ridiculously easier living together when you don't care about being seen nude. We all use the bathroom at once in the morning and stay naked the whole time, and of course we shower together. We share rooms, and now we're usually naked in them too. This is only a small look into our family, hopefully you're interested in more.