Anon has just left work and was heading home. He activated his omni-tool to message his girlfriend that he had a rough day. A couple minutes later, he received a message saying she was willing to help him "decompress". That message was all Mike needed to put a spring in his step.

When Anon made it back home, he rushed to get his clothes off and to retrieve some bathing supplies. Anon thought he should bring in a spare canister of his girlfriend's modified food paste. He made it to the decontamination room in between his girlfriend's room and the rest of the world. Once he was cleared for entry, Anon could now see his quarian girlfriend laying on her bed.
All 1500 pounds of her.

She wasn't always this huge, obviously. It was a long and indulgent journey to get to where she is today. It started with Anon being hard pressed to confess his secret fetish and she was all too eager to satisfy him. She started adding dextro-friendly sugar to her usual nutrient paste. The first taste of sweetness for the once taste-deprived quarian had her hooked for life. The sugar added a positive effect on her figure and her relationship with Anon while they did their sanitized lovemaking. As she grew bigger, sugared nutrient paste just wasn't cutting it anymore. Anon starting doing research into the dextro amino equivalent to culinary delicacies of his homeworld. Eventually her new addiction to sweets evolved into a desire to keep eating and grow bigger.

Her growth caused more than a few complications. Being a quarian, she was restricted to wear an environmental suit whenever she was outside her clean room. Whenever she would gain weight, her suit would grow tighter. Her girth would cause a tear in her suit and would need immediate patches and repairs. Aw she grew fatter, more and bigger tears would open in her suit. Eventually repairing the suit was just too impractical and she would spend the rest of her days of mobility in her clean room.

And so we come back to the present. Anon was standing stark naked in front of his equally nude alien blob of a girlfriend. As Anon approached her, he noticed she has just finished sucking down the of her highly caloric sludge. She took the feeding tube out of her mouth with a ponderously fat arm. "Did you... bring me more?" She breathed heavily. Anon brought up the spare canister food canister in acknowledgement. "Good... I'm still... hungry." Anon hands disconnects the feeding tube from the empty canister and reattaches it to the new one so that her feast will continue unabated. She took the tube in a clumsy, bloated three fingered hand and put it back into her waiting mouth.

Once she was occupied, Anon took on the task of cleaning her. He took the soapy sponge and wringed out most of its excess water and started to carefully wipe the quarian's face. She had grown a pair of chubby cheeks and a sizable double chin on her long neck. She closed her eyes while showing a small smile through her tube, knowing what pleasures were coming soon. Up next was lathering and rinsing her shoulder length raven black hair. Then came the arms. Each bicep was large and soft. They sagged downward into floppy bingo wings whenever she could muster enough energy to lift them. Then came her elbows and forearms which where being overlapped by her biceps. At the end were her hands. Each of her three fingers have grown extremely chubby, losing any dexterity she once had.
Moving back to her torso, her breasts have ballooned into large sacks of flesh. Each one was as large as a watermelon topped with thimble-sized nipples. The sponge brushing over the nipples elicited a small moan from the quarian. Anon smirked knowing she was going to do a lot more than moaning once he was through. Her belly was the biggest part of her expanded anatomy. It flowed from her abdomen, sagged on the edge of either side of her bed, rose high and obscured her field of view, and stretched all the down to her feet. It was truly a monument to her gluttony and to Anon's love for her. Anon had to stretch across his girlfriend to reach every fold and crevice of her belly. His erection would brush against her mass every so often.
Anon now had the Herculean task of rolling the obese quarian on her side to get to her back. It took a great deal of effort from both parties to achieve this but eventually they achieved enough momentum to do so. Her tits flopped over onto her arm as her belly sagged all the way to the floor. Anon began to work on her back rolls and rear end. Her ass was bulbous, dimpled, and would've formed a shelf if she were capable of standing. Anon rolled her onto her back again but still left her titanic belly mostly out of the way. Female quarian's naturally had wide hips. Her hips grew to the width of tree trunks. Below those monstrous hips were her buried kneecaps which topped off her swollen shins. The quarian had some serious cankles. Her shins were overlapping her chubby feet. Each toe was fat enough to rub against one another.
Now came the main event. Anon reached his hand under his girl friends waist to find her vagina. It took some digging but he found the fatpad leading to it. The quarian's silver eyes shot open in surprise before closing tight again as she moaned in pleasure.. Anon scrubbed sensually up and down her labia. Then he stuck a finger in, earning a gasp from her. Anon continued to move his finger in and out as she started breath heavier from the sexual action. He stuck in a second finger and increased his pace. The quarian was moaning louder from behind her feeding tube while she was in the throes of ecstacy. Anon's ears were met with a crescendo of her moaning as she orgasmed. Anon withdrew his hand and washed all of the quarian's juices off. There was a look of utter bliss on her face.
She started to give a him a suductive look while motioning with a heavy arm to her belly. Anon knew what this signal was. She wanted to repay him for all of his hard work. Anon climbed on top of his girlfriend and tried to straddle her colossal midsection. He angle his erection so it would sink right into her belly button.
They used to have intercourse after stuffing sessions all the time. At least before she got too large where conventional penetration became too difficult to achieve. They could still do oral or use their hands but it just wasn't as fun. That is until one day Anon had an idea. They were cuddle one night and Anon was wrapping his arms around as much as her huge belly as he could. His hands landed around her navel and his fingers slipped right in. Now Anon thought if he could fit his fingers inter her navel then surely his member could as well. And so they now have an alternative to penetration.
Anon started to slowly thrust into the depths of her belly button. This resulted in a wave of jiggling across her whole body. It reminded her of just how huge she has gotten. Anon started to pick up the pace as he was starting to really get into it. The jiggling was starting to reach her nethers, her fat toes curling in pleasure. Moaning, grunting, jiggling was all the could be heard from the couple. Anon's thrusting became faster and faster as he was approaching climax. They were in heaven, a glorious union of lust and gluttony reinforcing each other. They both reached their climax simultaneously. The quarian leaked more juices within her depths while Anon shot a hot load into her navel.
They both collapsed, exhausted from the exercise. Anon climbed across her expanse to reach her face. Their half-lidded eyes met. Anon removed the feeding tube and gave his girlfriend a deep, passionate kiss. "I... love... you." she said, extremely winded from sex. "I love you too" said Anon. Anon reinserted the feeding tube as they cuddled and basked in the afterglow.
They both looked forward to doing this again tomorrow.