It's a scientific fact that all booty calls happen after 1 a.m. All those cars you see driving around after 12:59? People out in the streets past 1? They're all on their way to a booty call.
#2 He gets frustrated when you invite him over to watch a movie and actually just want to watch a movie.
Most guys would be like, "Alright, cool. If I can't have sex, I guess actually getting to watch the entirety of The Hunger Games: Catching Fire is a pretty good consolation prize." But when you swat away his thigh-climbing hand he's suddenly tired and has to go home.
#3 You never meet his friends
The less information you have about him, the easier it is for him to ghost you. If you don't know who he hangs out with, or where he lives, or what his last name is, he can disappear like a phantom into the night. A phantom who banged you a bunch of times and then stopped answering texts, which would make for a shittier Broadway play than the kind of phantom that hangs out in operas. But a phantom nonetheless.
#4 He makes it really hard for you to sleep over
He never straight-up says you have to leave (That wouldn't get him a next hookup!) but he always has a "thing" really early the next morning. A "thing with friends" or "a work thing" or "some family thing." You know families don't have picnics at 5 a.m. though.
#5 He always hands you everything before you leave
Did you forget your bra? Some lipstick? Your purse? A single bobby pin? If you never forget anything there, you can never have an excuse to show up when he doesn't want you to. If you tried to show up unsolicited anyway, you'd probably find the place abandoned and boarded up, and some neighbor would tell you, "Why, that place has been abandoned for years!" like some episode of Are You Afraid of the Dark.