The first thing Cas becomes aware of is that his feet are freezing. He turns his head to look over his shoulder, blinking to clear his vision as the culprit for his cold feet comes in to focus.
Dean lays in a cocoon of the entire duvet.
Cas huffs and reaches for the covers enclosed around Dean, but stops as an idea occurs to him.
He eyes Dean's exposed leg for a moment before sliding his foot across the bed to touch it. Dean's leg shoots away as soon as he does.
Cas lays on his back facing the ceiling, chuckling to himself. He doesn't bother to look at Dean as he slides his cold foot further across the bed to come into contact with the same leg as before.
This time Dean only moves his leg slightly, so Cas points his toes to nudge him again, and Dean shifts his whole body further away from Cas.
Cas stretches his leg even further and places the length of his foot against Dean's calf. Dean shifts away again.
Cas shifts slightly closer and nudges Dean's leg with his icy foot again and Dean shifts even further away.
Cas goes in for the kill. He stretches both his feet across the bed and places one on Dean's calf again and the other slides up the back of Dean's thigh.
Dean abruptly shifts away.
THUMP.
And Dean's out of bed.
Cas catches the covers before they slide all the way off the bed and pulls them around himself as Dean groans from his place on the floor.