She loves surprising him.
Sometimes she makes a sci-fi reference and revels in the way his eyebrows shoot up towards his hairline, the way his mouth drops just the slightest bit open, the way his eyes widen.
She catalogs the times she's put that expression on his face.
It's a short list, but it's growing.
Like one of the first nights after they've moved in together and he puts on Arcade Fire's first album (she only knows it is because after the innocuous comment she maybe sort of looked up the album and then never mentioned it because the last thing she needed was Casey finding out and making some comment about peanut butter and chocolate but they're a Reese's now so.) and she replies only by raising her eybrows at him from the bed and asking,
"Are you trying to seduce me, Mr. Bartowski?"
For a second he sputters, then his eyebrows shoot up towards his hairline, and his mouth drops open the slightest bit, and his eyes widen.
Then a smile- his smile- stretches across his face.
And it's as if knowing what the music was without being told sets off a fire in him because faster than she can track (and she can track pretty damn fast) he's on top of her, kissing her and touching her and everywhere-ing her and he's right, this is an auditory aphrodisiac, and all she can think before he takes off her top and she stops thinking altogether is:
God, she loves surprising him.