Thirty-pack or no, it jolts him, head swiveling around in probably outrage as he says, "That never came up," on the topic of things shown him.

Clark has his own balancing act to do, not dissimilar to Bruce's. Sure, he isn't at typical Kryptonian brute force now, and sure, he is wrestling Batman who could probably do about twenty different things at every given pin attempt, but he's still formidable, and he doesn't quite know how much yet.

And so this kind of playfighting is probably reminiscent of interacting with an adolescent Doberman who isn't sold on not being a puppy. More prone to hurting itself, probably, but could leave a bruise when not paying attention.

But here, in this tangle, he reaches up and back to find where Bruce slipped his hand beneath his head, and before he can ease it away, Clark keeps it there, which keeps them close. His eyes are bright, and he hasn't quite stopped smiling since that first broke. Breathing harder, too, when normally that tends to only happen for feelings reasons.

"You're holding back," is not an accusation, but only because it's a fact. And a taunt.