Eren, as he often does, watches Reiner's mouth when he speaks. He's thinking about Reiner's mouth doing other things, though he hasn't moved into specifics in his head yet.

Besides, your mouth will be free, he says, and Eren's eyes jerk back up again. There's that telltale pink just touching his cheeks. He pretends it isn't there.

To his credit, he manages to say, "Yeah. I guess it will," though he doesn't quite manage nonchalantness about it. Of course he's turned on by the thought. Last time, he'd given up control but could have taken it back at any time just by shoving away with his hands. Without them, that's harder.

Fuck, why is that hot?

He swallows, as if that will clear up whatever it is that gets in the way of his words.

"Legs, I guess. If you did arms first it would be trickier to balance, I think."

He doesn't move away from Reiner's touch, but he does at least pull his shirt off. This isn't something they're doing fully clothed, right? Or at least he isn't; he hasn't graduated in his brain to considering that Reiner doesn't have to take his clothes off. Eren always leaps before he looks, not considering a whole situation like this, what the power dynamic inadvertently could fall into.

Not that he would care or stop or slow down even for a second.