Disclaimer: Not mine. Rating: R. ish. Set: s8, spoilers, etc. Pairing: Sam/Jack.
Notes: Liked the title, needed something to put with it. This appeared.

Theory of Flight by Ana Lyssie Cotton

She likes to make calculations on his back.

They're small, sometimes. Other times, they're huge and she ends up with her pen covering the skin of his legs.

He is always highly amused at her concentration.

"I've always been a visual person," she defends, on the off chance that he might object.

"This visual enough for ya?" he asks, and he turns, snakes an arm around her waist and pulls. And it's not visual anymore but tactile sensation.

"I was in the middle of something."

His fingers slide across her skin, and she shivers, "I could be in the middle of something."

The numbers dance along his skin as she kisses it, ignoring the way it smudges, and he mocks her for having ink-stained lips, although he admits to finding it rather erotic.

In her lab, when she's alone, and she writes on paper, she misses this.

He likes to count the freckles on her back and sides, the light dusting of melanin that got caught out by the sun. The number shifts and changes as she works or doesn't work. He still hasn't gotten her in that little black bikini.

"You're tickling." she accuses.

"Am not." But his fingers continue their movements. And he's suddenly right. He's not tickling.

Her pen ends up on the floor, forgotten, her mental energy changing its purpose away from mathematical precision and improbabilities to the man who is beneath her and around her and inside of her right this moment.

It's always good, when they're like this.

No cares in the world and no one to object if she screams like a banshee when she comes (not that she screams that often, but when he can make her do it, he is smug for days).

When he's behind his desk, she hopes he misses this.

They don't really talk about anything serious, when they're here. They've never talked about things like this. It's always been about tasting and touching and simply being. She never mentions Jonas or Pete or Martouf (although she only misses Martouf). And he never brings up Sara. They have talked, once, about Charlie.

Mutual agreement won't bring it up again.

When she's out in the field tramping on alien soil, leading her team and pretending that everything is right. That's when she thinks about her doubts. That's when she knows this isn't working, this isn't them. But then she comes back, and he half-smiles at her.

And so she writes equations in pen on his back.

Daniel once accused her of obsessing.

But, then, Daniel has never understood this side of her. Anymore than he has. Teal'c gets it.

She wonders sometimes, when he's asleep and she doesn't want to go searching for her pen, if Janet would have understood.

That's another serious subject she rarely thinks about.

It won't last, of course. Sooner or later, the Air Force will come crashing down on them. When they're ready to make him retire, or when the Joint Chiefs want her working only as a scientist. They will bring the pressure to bear against them and it will tear them apart.

Shreds of duty and honor versus being able to live in the moment.

For Sam, there's really only one moment left to her. It's this one, and it contains Jack.

"You think too much."

"I always have."

His fingers tangle with hers, and then he sighs. "There's a pen on my nightstand, Carter."

A smile tips her lips. "I know."