You have to invite him over to your place, let him sleep on your bed, move the pillow, kiss him and then there should be a 18+ option after that. On day 2 you have to wait for him and then go to his place, none of the options at first matter and then it doesnt matter what stay the night you pick and ask him to stay in your bed, i dont think theres a picture of that there. Accept the thing with Leon otherwise theres a jumpscare? I don't know what it's called, anyway the library dialogue doesn't matter just accept the date and then you can just skip the dialogue and invite Ren over when you get the option! Just choose any option during the eating choices and sit on his lap, theres no images for that either and then theres no more boombayah options as of now. ( sorry im rlly bad at explaining )