John's smile widens into a grin at Martin's agreement, and he leans back with a thoughtful hum. "Well..." he starts, studying Martin's back as he considers where to begin, letting his fingers trail idly over the gentle curves of him. Perhaps he'll start with the broad strokes, and then fill in the details. That seems as good an approach as any.

"They're all over, to start with," he says, and his tone could almost pass for academic if it weren't for the warmth that infuses it. "No particular areas of concentration. However, just here..." his arm stills, and his fingers trace the outline of a particularly evocative smattering of freckles tucked between Martin's spine and his right shoulder, "there's a little group of them that looks rather like a sailboat. It's almost uncanny."

His forefinger outlines the triangle that comprises the sail, and then he gently taps the topmost freckle. Usually, this is a courtesy that Martin shows him, a concession to the more nebulous nature of John's boundaries and preferences. But this feels like uncharted territory for both of them, and he wants to be careful. "May I?" he inquires softly.