Castiel may not realize it, but Sam does. He also doesn't draw attention to it. The fact that Castiel is reaching out for support and safety is...well, it may not be a good thing, but he's not keeping hold of the things that Jason gave him and that's something.

Sam slides his arm around Castiel, keeping his touch to the other man's lower back. A place that he can only hope, right now, that Jason left clear of marks simply because of how dangerous impact in that area can be. "When we get home, we'll get you a shower, yeah? And I want a chance to look at your back and wrists." Probably his ankles, too, honestly. "See if there's anything that needs treatment."

There will be. Jason seems to have been the kind of dom that enjoyed pain far beyond what his submissive was okay with. Something that was making Sam see red even as they moved.