I must have read this like six times. It hits so many of my favorite kinks: not so much the actual kinks, but the bit where they're clearly headed towards having sex and don't seem to notice, and the bit where one character is clearly a lot more aware of the attraction than the other, and the subtlety with which both are expressed. (The moment that got me was after the first time, and Sam's just standing there, frozen, mental blue screen of death. Holy shit, that was hot.)