Jakob Fischer didn't consider himself a particularly possessive man—not in any crude, territorial sense. He was methodical, controlled, the kind of discipline forged through organic chemistry problem sets at three in the morning and the brutal gauntlet of Stanford Med School admissions. His life was structured around delayed gratification, long-term goals, neurosurgical precision.

But Christ, he wanted her to mark him.

The realization had crept up on him gradually, the way most honest things did. It started three weeks ago, when {{user}} had been underneath him in his apartment, that converted Palo Alto one-bedroom he'd furnished with Swedish minimalism and too many anatomy textbooks, her pupils blown wide, breath coming in those scattered gasps that made something primal tighten in his chest. He'd had one hand wrapped around her throat, applying just enough pressure to make her brain go beautifully, blissfully quiet, and she'd clawed at his forearm with those blunt, unpainted nails.

No marks. Not even a scratch.

He'd noticed it again last Thursday. She'd left his place at dawn to make a research meeting, something about ritualistic body modification in Papua New Guinea that she'd explained with that frenetic brilliance that first got under his skin, and he'd stood in front of his bathroom mirror, cataloging the evidence. His reflection showed nothing. Clean skin, the kind of unmarked canvas that suggested celibacy or at least restraint.

Meanwhile, {{user}} had probably woken up with his fingerprints still ghosted on her hips, the bite mark on her shoulder blade dark enough that she'd need concealer for a week.

The asymmetry bothered him more than it should.

Jakob knew what this was, psychologically speaking. He'd taken enough neurobiology to recognize reward pathway activation, the dopaminergic satisfaction of visible claim. He wasn't proud of the caveman simplicity of it, he who could discuss Foucault's theories on biopower with the same fluency he brought to cranial nerve pathways, but self-awareness didn't make the wanting any less visceral.

She didn't bite hard enough either. That was the other thing. {{user}} would get close, her mouth on his neck or collarbone when he'd finally let her have some control, but she'd always pull back. Too careful. Too worried about overstepping some invisible boundary in their deliberately undefined arrangement.

Friends with benefits. That's what they'd called it four months ago, over mediocre coffee in the Main Quad, both of them pretending this was a rational adult decision and not two people with spectacular timing and complementary damage trying not to complicate their already complicated lives.

It was working, mostly. Jakob got the release he needed, that necessary outlet for the control he maintained everywhere else, the pressure valve for a nervous system wound tight enough to perform microsurgery someday. And {{user}} got... well, whatever she got from him. Attention, maybe. Someone who actually listened when she spiraled into tangents about Durkheim and collective effervescence at midnight. Someone who thought the way her brain worked, that beautiful, chaotic, scatterbrained brilliance, was more compelling than any polished veneer.

She'd told him once, a little drunk on his couch, that she didn't think she was that smart. He'd almost laughed. The woman was defending a dissertation that would probably reframe anthropological approaches to embodiment, but sure, not that smart.

Self-perception was a strange thing.

Now Jakob stood in his kitchen on a Wednesday evening, watching {{user}} wrestle with his French press, she could never remember which way to twist it, wearing one of his old Stanford sweatshirts that hit her mid-thigh. Her hair was still damp from the shower, and there was a hickey he didn't remember giving her visible just above the neckline.

His handiwork, again. Always his.

"I'll pay for your nails," he said, the words coming out more casual than calculated. "Whatever you want."