It's just a time honored tradition at this point, one he extends to Hange at times, too. It must be a Survey Corps Commander requirement.

He slouches a little more to extend his leg. It hasn't hurt for a long time, but it can still get stiff on occasion, particularly from under or over use. The touch is soothing, but Levi feels his pulse kick up a notch anyway, for reasons he can't quite articulate. The easy sweetness of Erwin's care will probably never not cause a fluttering in his chest.

"If you want, think I might have found it already, though." There's not many options in Somnius, after all. "But sure."

Some tension drains away, and he seems to finally fully relax his foot as Erwin continues massaging up his leg. Levi feels his eyes unfocus briefly, lids blinking slowly a few times. "...that feels good," he admits quietly.