A/N: More fluffy and mature content.

The next lecture he sits in on, the Doctor puts his hands behind his head, sprawls out, and simply glories in River. In watching her. In listening to her. He is more relaxed than he can remember being in far too long, and he is content to muse sleepily on her lecture notes without comment. It's amazing what few days in bed (well, when they made it to the bed) with his wife can do for his mood. He's rather forgotten that.

The students around him keep glancing between him and River, seemingly torn between their notes and the Time Lord stretched out in the front row, blithely not taking any notes at all.

He ignores them. He does not care in the slightest that they're busy trying to puzzle him out when they should be focusing on the carefully selected artifacts and accompanying explanations. River peppers her stories with references to their adventures that are innocuous enough for the listening students but leave him basking in memories of picnicking under solar flares and fighting Cybermen.

Admittedly, he should probably be a little concerned that he has fond memories of the Cybermen, especially given his last entirely too close encounter, but they've rather become his and River's pet monster over the centuries. They've certainly defeated them more times together than either of them ever has apart. And, at the moment, he's feeling just a bit too content to be bothered. His focus is on his wife. Neither students nor Cybermen are going to interrupt that.

Of course, his memories quickly take a more explicit turn, as any adventure with River is wont to do. The Doctor crosses his legs and shifts his coat over his lap as his languor fades, replaced with a growing desire to drag River right back to their new bed. He really shouldn't be entertaining such thoughts in the middle of her lesson but, as with everything else related to River, he finds that really shouldn't quickly becomes can't resist.

He manages to drag himself back to the present with some effort before he gets too carried away by fantasies, just in time for the lecture to let out. The Doctor smiles pleasantly and forces himself to stay just as he is, lest he be tempted to act on any of those fantasies before the auditorium has emptied. His limbs tend to have a mind of their own when it comes to River and his need to be as close to her as possible as often as possible.

Students mutter as they go around the other side or leap awkwardly over his crossed legs, but he keeps his eyes on his wife and ignores the rumors swirling across the auditorium.

River avoids so much as glancing at him until the last student has left, but he can hardly blame her. For all her teasing and bravado, he knows she'd been half-convinced she'd be sacked before this lecture after the wooden door incident at the end of the last.

He watches her put up her notes. "Have they assigned you an office yet?"

"Not yet," River sighs. "There's some red tape to sort through still, I believe. Why?"

She looks up and finally meets his eyes and it's all he can do to keep himself still and in his seat.

"You should lock the door."

River sets down the last of her papers very deliberately, and he can see the wicked smirk she tries to bite back. "Oh, really? And what makes you think I'd do that, after last time?"

He raises one eyebrow, incredulous. "What, we get caught once, and all of a sudden River Song is playing by the rules?"

"Not in the slightest, sweetie. I'm just surprised at your willingness to disregard them." She jogs up the stairs to lock the door before turning and regarding him from where he's craned his neck to follow her path. "Now what?"

"Come here."

River laughs, delighted at his audacity, and takes a much slower path back toward him, swaying her hips and teasing, "My, someone has grown up; haven't you, Doctor?"

As soon as she's close enough, he lets his relaxed pose fall away in favor of tugging her into his lap. "You have no idea," he murmurs into the skin of her neck.

Her skirt rides up as she settles across his lap, and he runs one hand appreciatively over her bared legs before trailing them higher, across the banded fabric until he can untuck her blouse. River has always been one to dress up for occasions, and he is quite fond of her Professor attire. Really, he's fond of anything she wears though, so perhaps he's a bit biased.

The Doctor rests one hand at the small of River's back, under her blouse and against her heated skin as he strokes his other hand across River's thighs until he can slip under her skirt and work his way back up.

"You can't keep staying after the lesson, Doctor. I'm sure lecture hall already thinks we're sleeping together," River cautions, even as her thighs fall open to give him room.

"We are," the Doctor points out reasonably, enjoying River's annoyed slap to his chest, even though River always hits hard.

"Can't you at least wait until we get back to our lovely little flat? They really might sack me if they think I'm dating a student." Her voice is a touch breathy as he hooks a finger under the elastic of her knickers and starts to tug them down.

"First off, you're not dating a student. I'm not on the roster and last I checked, River Song, we are very much married. As for making it back to the flat - it's too far away. You - I spend half the lecture imagining what I want to do with you when I get you alone. Hard not to, really, remembering just exactly what we got up to during some of your digs." He drags River's knickers down her thighs as he talks. She shifts in his lap, lifting her legs so that he can pull them all the way off. He tries to discretely tuck them into his pocket.

"Impatient," River accuses with an amused smirk that says he's caught out, and he can feel the blush spreading up his neck and face. "But then again, patience has never been our strong suit. Still doesn't explain you staying late two lectures in a row." She's keeping up the argument mostly to be contrary.

The Doctor taps his fingers against her spine in reproach, but both of them are far too distracted by his other hand, fingers trailing slowly back up River's legs, one at a time, stopping just at the crease of her thigh each time and enjoying the way her breath hitches with his light touches. "I'm reviewing the material."

Making a frustrated noise, River shifts one leg over the arm of the chair and parts her legs blatantly. "You already know the material." The Doctor raises his eyebrows and strokes one finger through her wet folds, and River groans around a gasp. "Oh, that's terrible."

"You're a terrible influence." He agrees, spreading River open with light, teasing strokes. "I shall have to file a formal complaint to the Dean."

River shifts on his lap, eyebrow winged. "You are welcome to review me any time you like, sweetie."

Instead of responding, the Doctor drags his index finger toward her entrance, just dipping inside as his thumb brushes across her clit. River makes a needy, keening sound that reverberates through to his bones. So he does it again, stroking through her folds and pausing just before he presses inside her, his thumb making lazy circuits around her clit before he retreats to stroke the soft, smooth skin of her thighs instead.

He soothes her with soft kisses against her neck as River digs her fingers into his shoulders, her breath coming fast and sharp and their conversation forgotten.

No, he's not normally a patient man. But for River - oh, he could - and has - spent hours between her thighs before. It's impossible to resist the lure of her body, the little noises she tries to bite back and the heady knowledge that River lets him take his time despite her own clear impatience.

When he finally slides one finger into her wet depths, River has to bite her lip to stifle a moan. The Doctor lifts his head to kiss her instead, rescuing her injured lip and running his tongue gently across it.

River clutches him to her, her mouth needy against his own. The Doctor takes his time, working her up and then pulling back again, caught up in the keening, demanding sounds River feeds into his mouth as her hips arch futilely toward his retreating fingers.

She huffs when they part for air the third time he works her just to the edge with his fingers, stopping just when he feels her start to tighten around him. His thumb continues to tease her clit, just light, intermittent circles across sensitive nerves - not enough to tip her over the edge.

"Trust me?" he asks, stroking his other hand soothingly across her back as he adds a second finger with slow, lazy thrusts.

"Always," she breathes, her voice hitching as his thumb catches her clit again.

He shouldn't ask that of her. But he'd be a better man than he is to resist her complete faith in him, especially because River knows exactly what kind of man he is. A liar. Selfish. And never more so than for her.

The Doctor works her up twice more, until River is trembling against him, her skin covered in a light sheen of sweat that leaves her blouse clinging to her. He ducks his head to lick at the hollow of her neck, tasting her, and River whimpers.

When she bends her head to demand another kiss, the Doctor acquiesces easily. He brings his hand from her back to tangle in her hair, holding her to him greedily, their tongues clashing messily as River struggles to catch her breath.

The Doctor curls his fingers up, increasing the speed of his thrusts and catching the spot that makes River gasp against his mouth. Her hands grab his hair, tugging, nails digging into his scalp.

He can feel her hearts racing and her muscles clenching. The Doctor finally brings his thumb back to River's clit, sliding across the needy nub with firm, rapid strokes as he presses his fingers deeper, harder inside her.

River screams when she comes, the sound muffled by his lips, insistent against her own. She falls apart brilliantly, her whole body shaking as a new rush of wetness soaks his hands, her inner muscles squeezing his fingers and her hands tugging sharply at his hair. He holds her to him and works her through it until he knows River must be nearly breathless, and only then does he let her pull away, gasping.

The Doctor wipes his fingers on the inside of River's skirt as he helps her shift her leg off the chair arm and pulls her skirt down. His other hand strokes through her hair and across her back as River catches her breath. He presses a chaste kiss to her lips, cradling her in his arms.

River's hands slide shakily to rest at his shoulders, and her lips seek out his, nothing chaste at all in the clash of tongues and teeth. The Doctor groans, reminded of his own, quite pressing need for her.

With a pleased hum against his mouth, River twists in his arms somehow and manages to slide her knees on either side of his hips, wedged against the arms of the narrow chair so that she is kneeling over him. Her hands slide to his trousers and River has them undone and is shoving them down with alacrity before he even realizes what she's doing. "Off," she breathes against his lips, her voice a low purr.

The Doctor hurries to comply, lifting his hips and shoving at his trousers and pants, and nearly falling off the chair before he remembers to plant his feet firmly against the floor.

River wastes no time. As soon as his trousers are around his thighs, she's wrapping one hand around his cock and guiding him inside her as she sinks down over him. Her inner walls flutter and clench around him, tight and sensitive from her recent orgasm, and the Doctor makes a choked noise, struggling not to come immediately at the silky hot feel of her.

There's not much room to maneuver, pressed so close together and with the damnably small chair hindering them. The Doctor scoots to the edge of the chair and wraps his arms around River's back, pressing her close as their hips rock in short, careful motions.

River's breasts are crushed against his chest, her arms draped over his shoulders to steady them on the back of the chair. Staring into her green eyes, flecked with gold and blue and blown dark in the wake of their pleasure, the Doctor finds the position intensely intimate, despite the fact that they are nearly fully dressed.

They've forgotten about being quiet at some point. Both of them gasping and moaning, the only sounds echoing through the large, empty hall.

He's going to come too quickly like this, his whole body already tight with pleasure and buried deep inside River as she clenches around him. "River -" and her name might be a whimper, the rest of his question lost to the rotation of her hips.

"Yes."

And River always knows because she answers his question anyway, bending to kiss him, the slight shift in position leaving them both desperate for each other.

He clenches one hand at her hip, dragging her down harder against him and relishing the tiny sounds that River tries to mask with her breathing and his lips. Her rhythm doesn't falter, even when he brings his other hand around to press hard against her clit.

She clenches around him and gives a cry against his mouth, and the Doctor is gone, thrusting up into her with abandon. The tight pressure thrums through his body and explodes as he spills inside her, his vision fading with the force of it.

The Doctor's hands shake as he wraps them back around River, their bodies still joined. River uses her grip on the back of the chair to keep them from falling, and the Doctor hurries to scoot up without actually separating them.

River lets her head rest on his shoulder, her breath stilted against his neck and her thighs trembling still over his.

"You really should put in for a not-wooden door," the Doctor muses when he has the breath to speak, voice low and croaky, wondering if that's exactly how the door comes to be replaced in the future. "It's safer. Anything can get through wood."

He can feel River roll her eyes even though her head is still pressed against his neck. She turns her head enough so that her voice is not muffled. "I'm hardly far enough in my tenure to be demanding they upgrade the accommodations. And anything, except your sonic. Why don't you just add a wood setting?"

It's a bit of a sore spot, and River knows it. A wood setting would actually be quite useful, more often than not. But he's not been able to get it to work, which River knows perfectly well. "I'd have to devote two whole wavelengths to wood," he grumbles against the warm feeling of contentment curling through his spine as he runs his hands along River's sweat-slicked back. "It does metal and electronics and nearly everything. No point in giving all that up just for wood." He eyes the frustrating wooden door balefully. Wood on the moon. Not nearly as catchy as Judoon on the moon. "Hang on - where'd they even get wood for the door?"

"Ah, but how will you build cabinets?" River teases comfortably, and he knows she's just been ribbing him to get him worked up. "And they had it specially grown. It's all very posh, I'm sure." She shifts finally, regretfully, lifting herself off him and sliding her legs to the floor.

"It's a safety hazard," the Doctor mutters, steadying her as she stands.

River manages to arch one eyebrow, glancing between him and the door even as she wobbles slightly in her heels and struggles to tug her skirt over her thighs. "It's safe as houses - not even you can get in."

The air is cool against sensitive skin, now that his lap is not full of a very warm River. Once he's certain she's got her footing, the Doctor moves to tuck himself away, though there's not much to be done for the mess she's made of his trousers and coat sleeve. "Are you trying to keep me out of your house, Doctor Song?"

River just sighs, clearly coming to the same conclusion that there is no way they're anywhere near decent. She unbuttons her cuff to reveal her vortex manipulator. The Doctor makes a face of disgust at the very suggestion, and River sighs again. "Maybe we should just park the TARDIS here cloaked. It would be closer."

Grumbling that it's not a very appropriate use of the TARDIS, the Doctor takes River's offered hand, their fingers lacing together as they stand. He rests his other hand atop the vortex manipulator, turning to kiss River again, his senses lost in her.

They're still entwined when they appear in their bedroom in her flat, the rough currents of the time vortex falling away and leaving them jarred and tangled together until it's hard to remember they were ever separate.

The Doctor squeezes River's hand and doesn't mind at all.

…