The lock he has around Bruce's thigh is almost so casual as to be negligent, and yet as unmoving as set concrete. In reality, nothing is truly negligent, Clark keenly aware of everything, including what he's doing, a thought behind each touch, each point of contact, happy to soak each little detail at his own leisure.

The baritone sigh out of Bruce stirs him, enough that Clark almost echoes it. Pulls Bruce's cock into his mouth, shallow again, and then deeper, sustained teasing and testing traded in for something firmer.

(The tug to his hair doesn't net a reaction, not an obvious one. Certainly not an ow. But if it triggers a memory, a dim and barely conscious sensation of what it had felt like when the indestructible nature of his material body had been compromised enough that he had known the prickle of pain of a hand grasping through his hair, firm enough to lift his head—)

Well, he's busy.