Well, me and my boyfriend both still live with our parents, and his are too conservative to let him even sleep over ( >:( ...he's 21 and I'm 19 btw) but when he drops me off at my house, he ALWAYS says to me "Goodnight, my Princess." It's so sweet <3 lol. We've been dating for over a year, and he's said this every night before he leaves. He's such a sweetie :D
I usually just say something random like "night night get in your bed and show it some proper loving tonight, sleep tight" , "dream of me munchkin" , "have a good time dreaming tonight and let's assassinate the haters tonight".