Their reaction to you giving them a backhug

Serim:

*will genuinely be the happiest person ever. He won't be shy or anything, he's just so over the moon about you showing your affection to him, and he won't stop gushing over how much he loves you.*

"You're so cute. Ahh, I love you so much. Give me more hugs please."

Allen: 

*is a little flustered and shook when you hug him out of the blue but he gets over it quickly and turns around and hugs you back.*

"What's the sudden affection for Y/N?"

Jungmo: 

*lets out an excited squeak and hugs you back, panicking for a second when he hugs you a little too tightly and thinks he's hurt you with his over-excitement.*

"I love you so mu- Y/N I'm sorry did I hurt you?!?!?"

Woobin: 

*freezes in shock for a moment and is really shy at first but then he can't help but pinch your cheeks and tell you how adorable you are.*

Wonjin: 

*playfully teases you and flirts with you about your sudden show of affection and even does aegyo to make you smile and laugh and hug him even more.*

"Ah, you like me a lot, don't you?"

Minhee: 

*immediately starts teasing you and flirting with you, to the point that you threaten to never give him a hug again.*

"You looooove me. Of course you do. Who wouldn't?"

"I am going to leave." 

"Nooooo Y/N please stay with your sweet loving Minhee."

Hyeongjun: 

*you've genuinely made him the happiest person on the planet. He gets really shy and doesn't say anything, just grins and blushes happily.*

Taeyoung: 

*happy virus energy to the max. Even with your arms around him, he can't help but bounce up and down happily and tells you over and over again how much he loves you.*

"I love you. I love you so much!"

Seongmin: 

*is super flustered and cannot stop blushing. He puts his hands on his face to try to hide how much you're making him blush and he whines loudly and blushes more when you pry his hands from his face.*

"Y/N, what are you doingggg? I'm trying to hide my blushing."