Rating: T. Here there be sex (but it be soft focus)

Disclaimer: Unsurprisingly, I own nothing. I merely borrow and return relatively unsoiled.

Summary: She's taught him how to say 'I love you' without a shell of humour. He's teaching her the history of mathematics.

Their bed is a blackboard, a teaching tool. Olivia feels too much and Peter talks too much and they both like to instruct. Now that they've mastered the elementary physics of where to touch and how and –ohyesjustlikethat- they've graduated to harder lessons. She's taught him how to say 'I love you' without a shell of humour. He's teaching her the history of mathematics. As yet Olivia's not convinced it's a fair trade but it's a rare Sunday with nothing to do except be in love so she's willing to follow where Peter's brain leads.

She snorts as his fingertips trace over the curves of her buttocks, explaining Mercator projection and the concept of linear rectification. Turns out she's not so hot for geography so she lies on her stomach, swinging her legs as he tries to explain how to transfer the spherical earth onto a flat map. Peter catches hold of her foot and pokes her in the sole.

"Pay attention," he admonishes her, laughing as she settles her head on her hands in mock concentration, before going back to laying out latitude and longitude on the curve of her ass.

He absently sketches the continents, sliding a finger deep inside of her and working through a slightly tenuous metaphor about the earth's molten core and the magnetic pole it centres on. She lets out a distinctly unladylike huff of laughter even as her back arches because, really, that was sailing a little too close to the wind of bad double entendres, even for him. He changes tack and bites down over Western Europe hard enough to make her yelp.

Five minutes later she's reversed the polarity, has Peter pinned with her mouth on him and her hands scratching at his thighs. He's staring to lose coherency but he's still talking about distortion caused by infinite scale. There's something truly satisfying in the sound of, "So any line of constant – oh, God – constant bearing is – yeah, just like, uh – is a loxo – God, 'Livia – loxodrome." But it's nothing compared to the triumph as she hums around him. His voice cracks over 'equatorial' and falls away. Then it's just expletives and encouragement, his palm cupping the globe of her skull as his fingers burrow into the oceans of her hair. He pitches and rolls beneath her until he sees stars.

At the lab he spars with Walter about the feasibility of genetic re-coding, absentmindedly toying with the light-up globe that appeared on a lab bench that morning. His index finger skates slowly around the Horn of Africa and she feels his fingertips teasing at the curve of her breast. His thumb traverses the coast of Brazil and she remembers his tongue on her hip. He glances away from Walter for a second and grins at her, knows damn well what he's doing, the bastard. Olivia flushes and excuses herself, hearing a cough that sounds suspiciously like Astrid trying to smother a laugh as she goes.