(If I offend anyone, I'm sorry. Gif credits to respective owners)
Minseok: You can't sleep without your stuffed animal and he can't sleep without you. He'd come home one day and find you sleeping on the couch with your plushie. He'd scoop you up and take you to the bedroom, where he would hold you in his arms like you do your plushie. "Ahh, look at you~ You look like my stuffed animal, all hidden in my arms. You are too cute for this world."
Luhan: You have your stuffed animal and he has his pillow. One night he would ask if you two could switch for the night, you'd agree with hesitation. You managed to fall asleep just fine but when you wake up you'd find him with his pillow and you with your stuffed animal. "Hey Y/N, I um...I really missed my pillow..."
Yifan: He would find it cute as fuck that you sleep with a stuffed animal. He would have trouble falling to sleep because he just wants to watch you cuddle and squish the animal. " Ahh, I've got a schedule tomorrow. I can't say up tonight....maybe 10 more minutes." He can't resist you.
Junmyeon: He loves seeing how happy they make you, so why not get more? You would come home after a long day and see Junmyeon sneaking out of your room. "Myeonie? Whatcha up to?" "Oh! Y/N! I was just preparing a surprise for you! Come here, lemme show you." He'd pull you to your room and as you look at your bed, you'd be med with a mountain of them. "Wow! Thanks Myeonie but....where are we supposed to sleep?" He didn't think that through.