Castiel can only groan softly at the suggestion. Sam's hands are are a kindness on his body. The mouth? The mouth would make him forget the reason for this kindness to begin with. Castiel finds himself wanting, nuzzling against Sam's face with a needy little sound because he can already feel his body trying to divert blood south again, his sensitive and for now spent cock interested in quick recovery.

The sight of Sam licking Castiel's pleasure off his fingers might only fuel that.

"Hmmmmy knees...?" he murmurs, distracted by the sight before his brain catches up on its higher functions and realizing what Sam will do. And Castiel feels undeserving, because he will have it all tonight, have every part of his body reclaimed by Sam thoroughly, and it's more than he could have ever asked for. "Yes, Sam. With pleasure."