It's hardly a thrown gauntlet; more of an easy agreement, which John likes even better. Martin might not be bursting with energy, but he has enough to play along. And there's something particularly charming about the implication that such care is simply his due — not because the idea is novel, but because Martin's comfort with it is. John's willingness to indulge him hasn't always been met with the idea that such indulgence is deserved.

"Right," John replies, moving the shampoo bottle aside and perching on the edge of the tub, cup in hand. "You asked for it." His smile softens, and he brushes his fingers through Martin's hair for a few moments before sliding his hand around to cradle the back of Martin's head. "Here, tip your head back a bit," he coaxes, leaning over a little to fill the cup with bathwater. No need to kick things off by letting Martin's hair drip directly into his face.