Can't say I've ever been naked in a library before, but if it were after hours and these were the circumstances then I guess it's time to undress. I was never late returning books though
You don't end up naked in between two girlfriends if you are still unsure about what you want, even with my friends it's a rarity we ever see each other naked, and when that happens it is usually when we are trying stuff on or getting ready to go out