Sam wakes Dean up in the middle of the night, they exchange hushed whispers as a sleeping Castiel lay curled around Dean's torso. Dean gently extracts Cas from his body and follows Sam to help him with research.
An hour later a drowsy Castiel stumbles in. Sam and Dean look up.
" d'need m'ssitance?" Comes Cas' mumbled question.
Dean walks over to him allowing Cas to wrap his arms around his torso and rest his head on Dean's shoulder as Cas' eyes begin to droop.
" Nah, I think we've got it covered" Dean sqeezes Cas' shoulder, "we should get you back to bed" Dean attempts to extract Cas'arms from him but Cas tightens his hold and buries his head further in to Dean's shoulder.
"Angels don't nee' s'eep" comes the muffled response.
Dean let's out a breathy laugh "Yeah maybe not, but right now you do" he finally succeeds in untangling himself from Cas' arms and attempts to guide Cas back to bed.
Cas moves to Dean's side only to wrap his arms back around Dean's torso and lean his exhausted body against him.
Dean chuckles " Alright you clingy bastard, lets get you to bed" He shoots Sam a pointed look while half dragging a rather uncooperative Cas out of the room.