[That has a visible effect, in the way Sion shudders and squeezes Naoto's hip with his fingers, lips parting slightly, eyes narrowed but pupils completely blown.]

[He leans down, letting go of Naoto's hip to brace his hand by his head, the other still guiding himself as he pushes slowly into Naoto, face inches from Naoto and just, watching his reaction. Holding eye contact.]