Psst, Chel, so... does Kakashi ever sleep in the nude? Or at least, mask and nothing else?
Let me start by saying that Ka is always dressed for the occasion and sometimes the occasion calls for us in matching birthday suits.
If you're fishing for details, I'll at least tell you that his mask does tend to remain. It's more like part of his personal identity and less like an article of clothing to discard during adult extracurricular.
However, we do also have a child who does get saddled with the occasional bad dream and he'll crawl into bed with us. Normal late evening wear are things like jinbei and Suisei has a few costume pajamas that still fit. Oh! We had this one that he just grew out of that looked like the village uniform, they were both so bummed when it was time to give it up. I think they like to match, really.