BTS reaction to you falling asleep on them while you cuddle:

JIN: He would smile slightly and put his arm around your waist. He'd brush away small strands of hair from your face, and eventually  put a blanket over the two of you and then fall asleep.

SUGA: He wouldn't notice at first but when you start to snore lightly he'd kiss your forehead and smile. He would give you a piggy back ride into the bedroom and carefully put you on the bed and tuck you in tons of blankets to keep you warm. 

RAPMONSTER: Rapmonster wouldn't mind you sleeping on top of him so he'd try to keep still to prevent you from waking up. He would plant a few kisses here and there and eventually fall asleep snoring together with you (lol).

J-HOPE: Hobi would have a bright smile on his face and hug you tighter. He'd play with your hair and kiss your cheek. If he accidentally woke you up he would feel guilty and apologise over and over again, but you'd just laugh at how adorable he'd be.

JIMIN: Jimin wants to keep you comfortable at all times so he'd change your clothes into your pj's and carry you to bed. He would get ready to sleep himself, so when he'd be done brushing his teeth he would crawl into bed next to you and fall asleep with his arms around you, keeping you safe.

TAEHYUNG: Taehyung wouldn't really know if he should wake you up and tell you to sleep in the bed or if he'd keep cuddling you. But in the end he fell asleep with his head on yours. 

JUNGKOOK: When he'd notice that you'd shift frequently and hug him even tighter he'd get pretty flustered. When he'd see that you're asleep he would draw invisible lines on your forearm so you'd relax more. Later on he'd get up from the couch to put a blanket over you and a glass of water beside you.