While she appreciates the care, she has her preferences. She lifts her mouth from him for a moment to say, "Move how you want. I'm tougher than I look. I'll stop you if it's too much. Promise."

That's part of the appeal. He's big and she's small, and he can manhandle her in ways Arthur won't, because he's so careful with her, even when they get rough. If Eames wants to be gentle, it's more than fine, but she doesn't want him holding back on her account. Because she can take it. She likes taking it.