A/N: Ok. Remember when I said no more fan fiction from me? I lied. There will be more fan fiction. Just not that often. And I'll probably just write oneshots as and when inspiration hits me. This Fatlock oneshot was inspired by a prompt on my fatlock blog. You can find me on Mycroftsumbrellaismadeoutofcake.

The prompt was: Jim punishes Sebastian by force feeding him and mocking him about how stuffed he is and how fat he's going to get because of it.

DISCLAIMER: I don't own the show. I don't own anything.

Sebastian watched as his boss circled him with inspecting eyes. His tense muscles shuddered beneath his skin tight t- shirt, almost as though his body was aware of all the rules Sebastian was about to break.

"You've been stuck in your ways for far too long." Jim hissed down his ear. "All that exercise, all that careful eating. You're far too uptight."

Sebastian's breath hitched in his throat. "What do you propose to do about it then boss?"

Jim reached out to him, placing his small hands on Seb's hard pecs. He pushed him lightly and Sebastian fell backwards onto the king sized bed with a soft gasp.


Sebastian was cut off when he felt a large custard filled donut enter his mouth. He choked and tried to take the disgustingly fatty food out of his mouth but it was impossible as Jim was now pinning his arms down whilst somehow forcing his head backwards, giving him no other choice than to chew. The smaller man was surprisingly strong. Sebastian was unable to push him away, though part of him didn't want to push him away. With an inward groan he finally allowed the donut to enter his system.

Before he could ask Jim what the hell did he think he was doing he found another donut being pushed into his mouth. This time a jam flavoured one. Oh. So this was the game his boss was playing then? Perhaps if he played along he would lose interest. Sebastian chewed, swallowed, chewed, and swallowed again. The donut hit his stomach with a heavy thud and he groaned.

Instead of seeing Jim defeated however, which was the response he'd been expecting, the smaller man seemed delighted.

Jim patted Sebastian's hard, flat stomach, almost like he was praising a puppy. "That's my Seb, taking his punishment, like a good soldier, getting nice and fat for me."

"I'm not fat!" Sebastian protested.

" you will be soon." Jim hissed.

Sebastian snorted. "I won't let you fatten me up like some prize turkey!"

"Oh. But you have no other choice."

Jim carefully removed himself from the sniper and Sebastian went to lunge at him. Except he found that he couldn't. He grunted in surprise as his body slammed back against the bed. "What have you done!?" He asked, exasperated and completwly baffled by the way his body now unable to move.

"Have a look, Love."

Sebastian craned his neck to see that Jim had tied him to the bed with metal restrains. He tugged at them as hard as he could but they just wouldn't budge. " Jim..."

"Shh." Jim placed a finger on Sebastian's lips. "It's ok, Sebby baby. Don't fight it. Take your punishment."

Sebastian had a bad feeling about this. He swallowed thickly and nodded. It was all he could do.

Jim smiled warmly at him. Seb knew that smile well. It was the smile that told him Jim was planning something big.

His eyes bugged from his skull as Jim clicked his fingers and the trays of highly calorific food was wheeled in.

"Shit." He mumbled.

"Wash that mouth out!" Jim snapped. He grabbed hold of Sebastian's jaw and suddenly he found his mouth filling with full fat milk. He choked in pained surprise and some of the liquid spilled down his chin.

For a long few moments the only noises to be heard were the loud glugging sounds of liquid moving down Sebastian's throat.

He could feel the unfamiliar sensation of his stomach filling. It was filling too rapidly. It hurt. The pressure was becoming immense. He struggled and groaned, trying to get the torture to stop.

Jim eventually pulled away. By this point Sebastian's stomach was round and hard and sloshing with fatty milk.

Sebastian spluttered and scowled. "What the hell?"

Jim merely smirked.

Seb closed his eyes. He knew his punishment was far from over.

His thoughts were only affirmed when Jim forced his jaw open and a slice of greasy pizza was shoved into his mouth. He didn't even try to resist. He knew that it would be best to ride out his punishment.

So that's what he did. He ate slice after slice of pizza, pushing past the pain. His throat was raw from swallowing and his stomach felt like it was about to explode, it was so full. He was not used to eating so much and that fact was starting to become incredibly obvious. "I'm going to be sick." He mumbled.

He felt Jim's delicate fingers pressing into his hard, full stomach and he groaned. "Burp, love. You'll feel much better." With another push from Jim's fingers he found himself belching loudly. "Better?"

Sebastian nodded. He still felt horribly bloated and queasy from all the contents he'd consumed but he did feel a little better. "Is my punishment over yet?" He immediately knew it was a mistake to have asked such a question. He scolded himself inwardly and prepared himself for what the Consulting Criminal had in store for him next.

"Oh honey, wouldn't you like to know."

A hot and salty chip was placed on his lips. Jim's eyes twinkled deviously. Sebastian's stomach gurgled, a threat to tell him it was going to fight back if he tried to fill it further. "I can't..."

"Oh." Jim's face fell into a pout and he removed the chip. "Is my soldier refusing to take his punishment? Refusing to take the consequences of being such an uptight arse?"

Suddenly Jim's lips were smacking against Sebastian's too full stomach. He gasped. That had been the last thing he'd expected. A hot wave of pain/pleasure rippled through him and travelled straight to his cock. This was a rather new and unexpected turn in his relationship with Jim, but it wasn't entirely unwelcome.

He pushed up against Jim's lips and whined pitifully.

"Oh." Jim smirked. "You like that?" Sebastian whimpered again and nodded. Jim pulled back and eyed Sebastian's rather prominent erection, humming in satisfaction. "You were always my favourite, you know."

"I was, Sir?"

"Yes. You still are. I've always wanted more of you. I can never get enough." A hot kiss was placed upon Sebastian's neck.

Sebastian's cock twitched and strained against his trousers. "May I just say, I've always wanted you, like this, but I just didn't think you'd be interested." Sebastian was embarrassed to find himself blushing like a schoolboy." I mean, don't really think I'm your type is all."

"Oh. You've got that right. You're not my type. You're not far off it though."

Sebastian swallowed. "Oh. How so?"

"I like my partners to be a little more relaxed than you are. Like I said, you're far too uptight. I also like my partners to be..." A huge grin spread across his face. "Bigger than me. Much bigger."

Those words hit Sebastian like a ton of bricks.

"Oh. You mean...?"

"Yep. So tiger, you have a choice. I can release you now, nice and easy, and you can piss the hell off. Chose that option and I never want to see your face again."

"I don't like that option at all." Sebastian felt his already upset stomach tie itself into a thick knot. The thought of never seeing Jim again was sickening.

Jim smirked, all too aware of what Seb was thinking. "Option two. You let me punish you, let me keep you chained here, and you eat. You get nice and fat and you learn how to relax. Then, if you're a very good boy, if I deem you fat enough, I'll reward you."

Sebastian found himself actually drooling as his mind suddenly began spitting out various dirty images of him and Jim together, like he'd always dreamed of. Oh. He definitely liked option number two, well he rather liked the sound of being rewarded by Jim, the whole getting fat thing didn't sound at all appealing though. It went against all of his army training.

"Well? What's it going to be Sebby? How much do you want me?"

Sebastian licked his lips. There was still a trace of salt left on them. "I'll...I'll take option two."

"Good choice." Jim patted Sebastian's stuffed belly. "Look at you. You're so full, so stuffed. I think that you rather like this little game. You're not putting up much of a fight. Do you want to be my fatty? My big, useless sniper. Hmm? Well? Answer me!"

"Yes!" Sebastian cried softly before he could even stop himself. Jim was pressing down hard on his stomach now and the cry had been involuntary.

Jim smiled, clearly pleased with himself. Four ketchup covered chips were jammed into Sebastian's mouth.

There was no backing out now.

1 year later.

Sebastian was definitely fat now. Fat was probably an understatement. He no longer has any clothes that fit him. He was forced to be naked, splayed out on the bed like a prize hog.

His hard abs were merely memories now and his gut was so large he looked like he was a man attached to a stomach, rather than the other way round. How Jim could find him attractive like this was a mystery, but the consulting criminal really did. He reminded Sebastian of the fact on a daily basis.

Like right now for instance.

Jim was pressing needy kisses to Sebastian's huge jiggling gut. Sebastian moaned like a cat in heat and reached out a meaty hand to grab hold of a fistful of Jim's hair. (Once he'd put on the first five stone Jim had allowed him to be free of his restraints.)

"Look how fat you've gotten." Jim teased. "Far too fat to get off your arse. Mmm. Talking about your arse-"

A rather girlish squeal escaped Sebastian's lips as Jim began to kneed his fingers into his fleshy bum.

Jim chuckled and moved his lips up Sebastian's big body, taking special care when he reached Seb's meaty neck, nuzzling against the flesh there. The small sensation of Jim's nose sinking into his fat sent shivers through Sebastian.

"So, love, does this make your punishment worthwhile?" Jim whispered huskily.

Sebastian grabbed Jim and pulled him up for a deadly soft kiss, their lips moulding together perfectly. Jim wrapped his arms around Sebastian's ample gut and squeezed him tight. When Seb pulled away from the kiss he was breathless and red in the face but he was wearing a huge grin.

"Completely worth it."