Take Philip's absolute, utter mortification, and now multiply it by infinity. At first Dean thinks he's hiding the embarrassment well: head ducked, shoulders a rigid line. But the heat is increasing and his cheeks are burning and his stomach is flipping in that way that only happens during freefall on a roller coaster - or in Dean's case, any occasion when he's seated on an airplane.

Cas just...in front of Phil...

...and in that instant Dean loses any hope of his friends becoming friends, and shoots Castiel a look that says We are talking about this later, you tactless dick.

Because it's not already bad enough that Philip and Cas appear to have gotten off on the wrong foot without Dean to supervise. Castiel was being presumptuous with a whole slew of things - for one, assuming that Dean would...y'know...take it like some bitch. Then there's the issue of bringing it up in public, but for some reason that bothers him less than the idea of bending over for some other dude.

Even if he likes the other dude a lot.

It's just emasculating, man.

So he flushes dark red, keeps his own head down, and steps up the pace to get back to the mansion, so grateful when they finally reach the foyer.

"Uh," Dean's voice is tight with anxiety and anger, but he nods quickly at Phil. "See you around, man. Stay...stay outta trouble."