Hakkai settles in against him, head on his shoulder; a shiver catches him as he lets his weight rest on Eiffel. It's subtle enough that he could've hidden it if they weren't touching, and for a moment, embarrassed, he has to quell his own urge to scoot away.

He does want this, does care deeply for Eiffel, but that doesn't make it easy to lower his personal boundaries.

But he's also stubborn, and so he stays, even scooting in a little closer.

Against Eiffel's neck, he mutters, "If you disappear again tomorrow, I'm swearing myself to strict monogamy for life."

Being careful isn't really about being good to Eiffel. It's a very important side effect, but Hakkai is being careful with himself, too, right now.