Dean’s leaning against the driver’s side of the Impala, facing Sam, who’s doing the same on the other side of the car, when Cas shows up in the front seat. The car looks to be parked on the side of a normal neighborhood street, and it sounds like the brothers are discussing their current hunt - they’re wearing their suits, so he suspects they must’ve just come from an interview. If Cas were to look, he’d probably see files and other papers strewn about the top of Dean’s baby. Cas sees this as the perfect opportunity to get Dean back for what he did at the diner, let him know that two could play that game.
The driver’s side window is down, allowing Cas to place one hand over the crotch of Dean’s slacks, rubbing small circles and feeling the bulge grow under his touch; his other hand is used to thread his fingers through the loops of Dean’s pants to keep him from pulling away too much. The look in Dean’s eyes when he glances down quickly switches from defensive to confusion then finally melting away into lust when he sees the angel.
“Everything all right, Dean?” Cas can hear Sam’s voice filter down into the car, and Dean’s head snaps back up at the question.
“Yeah, I’m great.” And Cas can just imagine Sam’s look of confused concern directed at his brother right now, but Dean goes on acting like nothing happened. “Uh.. so you were saying you think you might have a connection between the three victims?”
Cas’ fingers made quick work of Dean’s belt as he tunes out the rest of the Winchester’s conversation, mouthing at Dean’s cock over the layers of clothing, already getting impatient to have it in his mouth. The button and zipper follow easily once the belt is undone, and he can feel Dean tense as he slips a hand into his boxers.
Pushing Dean’s shirt up and pulling the elastic of the underwear to settle just below the hunter’s balls, he frees the erection from it’s confines. His strokes are even, thumb sliding under the head, working Dean up for more to come. Precome starts to bead at the slit as Dean tries to push in closer, though from the sounds of it, he’s still carrying on his conversation with Sam just fine.
That just won’t do.
“You think it’s a what? A taniwha- AH, fuck!” Cas swipes his tongue from the base of Dean’s cock to the tip, swirling it around the head once, enjoying Dean’s slip-up.
“Dude, you sure you’re okay?” If only Sam knew how okay Dean really was..
Dean plows on. “Yeah, yeah, ‘m fine, Sammy. Just banged my knee on the car or something. Anyway, aren’t those things supposed to be guardians of the sea or something?”
To reward Dean for doing so well, Cas takes the head into his mouth, lapping at the precome and letting it pool on his tongue. He loves the taste of Dean and savors it by swirling it around on his tongue before tugging on the belt loops and taking him in as far as he can go - and since he’s an angel with no gag reflex and no need to breathe, that’s pretty damn far.
One of Dean’s hands comes down to thread it’s fingers into Cas’ dark hair, and he has to hold himself back from moaning. Even while preoccupied with something else, Dean has to take charge, tugging on Cas’ hair and fucking his face on Dean’s cock. The weight of Dean on his tongue is intoxicating, and Cas does his best to keep up, hollowing his cheeks and swirling his tongue on every upstroke.
He hasn’t been paying attention to the conversation, but Sam hasn’t started yelling yet so Dean must be doing well not to let on what’s going on.
With Dean taking control, Cas’ hands are free to do other things. One he has gently cup Dean’s scrotum, fondling the balls between his fingers; the other he wraps around the base of Dean’s cock, a couple fingers splayed along the shaft so he can take them in, wetting them with saliva as well before reaching back across Dean’s perineum finger at his puckered hole. One slick finger breaches the tight rim only to the first knuckle at the same time Cas deepthroats Dean and swallows. The result is an incoherent noise and something slamming against the roof of the Impala as Dean shoots his load into Cas’ mouth, which he dutifully drinks down.
As much as Cas loves to revel in the taste that is Dean, he hears Sam say, “I think we better get back to the room. We can figure everything else out later,” as the passenger side door starts to open.
Cas has Dean tucked away and presentable in record time, and is in the backseat when Sam gets in the car. “Hello, Sam.”
For a moment Sam’s quiet, a look of consternation spreading across his features like he’s warring with the thoughts inside his head. It isn’t until Dean’s in the car and they’re on their way back to the motel that he seems to finally settle on something and says, “Next time, Cas, wait until we’re back at the motel when you feel like blowing my brother.”
Dean jerks the wheel, swerving slightly. Cas just nods, face impassive as always. Sam’s a good brother.