Mutual gaining Sterek where they’re so large that neither of them can reach the wheel of the car past their stomach, though both insist they still can, and sex is more mashing their stomachs against one another and rutting against their fat since it’s too much work otherwise. Theyre at the point where they need a loveseat each for themselves with a funnel attachment to constantly drink from between meals since their appetites are just so insatiable. They initially argue over who has to change out the shake after they run out, but after getting even bigger the become too lazy and just have someone else come over to do it for them. Having others help then only exacerbates their laziness and furthers their rapid expansion.
They're the couple who doesn't start off trying to gain. It's all lazy, content relationship weight. Derek cooks on weekend. They get pizza or takeout most days after work because neither one feels doing dishes. There's more than once when they're not nearly 'too big' for sex, but too full. So instead it's mutual hand jobs on the couch with greasy hands. They eventually have to talk about it. When it's clear the relationship weight has been pushing into "intentional gains." Because Derek and Stiles are always competitive, eating is no different. Who can finish the last egg roll. How many pizza slices can they each eat? How many tacos before one of them has to tap out? They agree to hit an nice, even number. 350. Big. Properly obese. But nothing...too much. Reasonable. Just two out of shape guys who involve food a little too much in their relationship. Except it doesn't stop there. A little experiment in gaining changes to them becoming full on gainers. Pushing themselves to eat more. Who can reach 350 fastest. Derek will wake up to Stiles chugging a shake in bed. Stiles catches Derek stopping for fast food before coming home from dinner. They're both comparing- whose gut is biggest? Whose thighs are widest? Who has the roundest ass? Until someone hits 350. Which...they agreed to stay around there, but then it becomes "First to 400?" Which...still isn't enough. Everything is a competition. Stiles celebrates being the first one to pop a button and Derek says so what - the seam of his pants split down the middle today. Derek gets stuck in doorway, Stiles needs help unwedging himself from behind the drivers seat. They start having competitions daily for fewest steps taken. Most calories consumed. Fully kink first- practicality of their sizes second. Their texts are just proud milestones. Couldn't fit in an office chair. Derek too fat to fix cars and sells off his shop. The 'my dad thinks I should go on a diet' or the 'Peter thinks you're a bad influence on me'. When they both start getting tired out- because no matter what position, all that thrusting is a LOT of exercise - they're not bothered. Stiles will jerk off on the couch as Derek tells him to keep eating. Keep up. He's never going to be a fat pig like Derek if he's not eating until it hurts. They could get off on the dirty talk and teasing alone. Or taking huge, overflowing handfuls of blubber and shaking it, pointing out every new roll and stretchmark and wondering how much bigger they're going to get. They'll be the couple in bed next to each other-belching and huffing in their rare breaks from feedings - "How many inches is huff my belly wheeze now? Bigger urrrp than huff his?"
