Sherlock relishes her stare, drinks it in. Because he suddenly understands something without having actually deduced it: she's feeling the exact same surprise and delight at discovering things about him she didn't expect that he feels about her.

Which is both an emotional lift and, somehow, a turn-on.

He licks the last slick taste of her off his thumb, lets his hand drop slowly so that his palm rests against her shoulder. They're probably both going to need another shower later.

"Amazing," he says quietly, and means it.