Clint really likes Phil Coulson's neck.
In fact, if someone ever asked Clint which part of Phil he liked best, Clint would most definitely say, "His neck."
But Phil's mouth is running a close second.
The best thing about Phil's neck is that it's so… sensitive. One of those spots. Every little brush of the lips, every little nip, takes his handler closer and closer to the edge, begging for Clint to fuck him.
And Clint is only too happy to comply.
Not to mention, Phil's neck is ridiculously strong. Clint doesn't know if it's a "Coulson thing" or what, but appearances definitely deceive when it comes to Phil's neck. Those are some muscles that have no right to be as attractive as they are. Like on that one memorable occasion where Phil pushed Clint against a wall and held him there for an extended, enthusiastic marathon of fucking. It wasn't like Clint fought him (much). But Clint loves to marvel at Phil's neck, to feel those lovely muscles under his fingers.
Those muscles. Let Clint just rave for a minute here. They aren't the big, thick kind that Steve or Tony have from labs-slash-super-serums or gyms. These are the ropy kind, the ones that always remind Clint of a feral animal. And Clint, of all people, does not deny that Phil is an animal. A wild one. One that attacks viciously, with a fervor usually only reserved for obstinate paperwork or a particularly remarkable book.
Oh, and his mouth, God, how Clint loves Phil's mouth. Once it had been uncharted territory, but, over time, Clint has been able to stake a pretty definitive claim to that territory. Now Clint is quite familiar with Phil's mouth. Especially his teeth, did Clint mention those? They are quite intriguing. They raise the most curious emotions in Clint that he's never felt with anyone else. Like when they nibble on Clint's bottom lip. And then he finds himself making noises akin to the ones Phil makes when Clint kisses his neck.
Yes, Clint really likes Phil's neck.