I was unsure if you meant sleep in the SFW or NSFW sense, so I did both!
SFW
Kaneki Ken – he loves to lay his head on his partner’s chest or lap.
Kirishima Touka – She is the big spoon.
Fueguchi Hinami – if they’re not hugging her what’s the point of sleeping together?
Nishiki Nishio – must be facing his SO, so their face is the first thing he will see.
Nishino Kimi – holding hands.
Tsukiyama Shuu – constantly uses French and English phrases to praise his SO even in his sleep.
Renji Yomo – he’s a cuddler. Arms firmly wrapped around his so, pressing them close to his chest.
Uta – will probably use his kagune to cocoon the two of them together.
Yoshimura Kuzen – one gentle arm strewn across his beloved.
Enji Koma – he’s kind of an acrobat in his sleep, so they might need space between them.
Irimi Kaya – they must each be piled under a mountain of blankets, no matter how warm it is.
NSFW
Kaneki Ken – has a habit of crying with happiness afterwards. more passionate in the bedroom than he is at most other points in his life.
Kirishima Touka – She loves experimenting different positions.
Fueguchi Hinami – gentle, butterfly position sex is her favorite.
Nishiki Nishio – roleplaying is fun.
Nishino Kimi – is a fan of sex in the morning.
Tsukiyama Shuu – will pepper his beloved with praise the entire time.
Renji Yomo – he’s hesitant and afraid he will hurt them, and very emotional.
Uta – cracks jokes, tries crazy moves, probably fond of some bdsm.
Yoshimura Kuzen – very sweet.
Enji Koma – will use his kagune to add extra spice.
Irimi Kaya – fierce. lovemaking is its own kind of battle.
Mercy and Magic 