@BugDevil
I'm not one of those who claim they had sex, let's go one step at a time and before long, they'll be holding hands (oh wait, that already happened) (I'll be the pessimist this time, because I don't think we'll ever get a second season, the sales are good(?), okay, but that's most likely because of the code or something that comes with it).
Using your own words "they will live together soon", with that in mind, Anne would find out about Grea's sleeping habit sooner or later, so might as well already get that out of the way, considering that's the only reason Grea was avoiding the sleepover, and as far as "one step at a time" goes, I think this much is acceptable, unlike the bear pajamas, of which Grea would still be too shy to go along. Or at least, that's how I see it.