Only Levi, and occasionally Hange, get Erwin's massages. He's just realistic about his abilities.

When Levi reaches for his hand, Erwin is fast and eager to lace their fingers together. He holds Levi's hand as he kisses ever closer to his cock, only stopping when Levi messes with his hair. He goes still then, letting Levi do whatever he wants with it, and then looks up through his bangs and smiles.

"You just can't resist mussing it, can you?" It's not a complaint; it's one of the ways Erwin knows Levi is relaxing and enjoying himself. If he's feeling confident enough to mess up Erwin's hair, that's a good sign! Erwin also knows Levi likes the way he looks when his hair is out of order, and his eyes twinkle behind the shield of his fringe.

But that's enough preamble. Erwin plants one last kiss on the supple, pliable skin where Levi's leg meets his groin, then repositions himself so his head is directly over Levi's cock. He takes a moment to enjoy the view--Levi isn't large anywhere, including here, but he's perfectly formed and somehow managing to look strong and capable--before bending low and pressing his lips to the base. From there, it's a long, slow slide to the tip, Erwin pressing his tongue flat against the shaft.