Ruby Rose was making what most people would call 'a mistake'. Most people would definitely have considered the many packets of cookies that Ruby had just eaten excessive and would consider the sore round belly proof of that. For Ruby, that was just a sign that she needed more practice at overeating cookies. At least that was her explanation for the exasperated Weiss.
"And why is that something you need to practice?" Weiss asked, rolling her eyes.
"Ozpin and Professor Goodwitch made me the present deliverer for Nondescript Winter Holiday, so I gotta get in character. Do you know how many cookies Jolly Redman has to eat in one night? I gotta eat an entire school's worth of holiday cookies," Ruby exclaimed in surprising moment of clarity.
"Ruby, that is…" Weiss let out a sigh. "You know you don't have to eat all the cookies, right?"
"If I don't, who will? They'll go all stale and stuff if they get left out all night and everyone will think that Jolly Redman didn't show up," Ruby explained. "Besides, I gotta get in shape if I wanna be Jolly Redman. If someone catches me, I gotta look like the real guy, not this twig," she added, gesturing to her body as she lay in her bunk bed. The taut round belly was somewhat undermining her message, but it was very well contrasted by the rest of Ruby's petite frame, especially with how snug her winter pyjama top was around it and how ready one of the buttons were to try and escape.
"Well, if you're certain…" Weiss began.
"Oh, I totally am. Coco even gave me some stuff to make me really big really quick and she's gonna give me some stuff to make me slim again afterwards. So, yeah, no need to worry about me being too big to be a Huntsman."
"Fine. But you're getting the bottom bunk. I don't want you coming back from delivering presents and crushing me," Weiss relented.
"Ugh, fine. I'll move once my stomach stops hurting."
-s
Nondescript Winter Holiday's Eve was soon upon Beacon Academy and Ruby was ready to be the best Jolly Redman Beacon had ever not seen. Being seen, however, certainly wouldn't be the end of the world thanks to Ruby's new physique. This thought was brought to Ruby's mind by how stretched her Jolly Redman costume pants were, as they would probably have looked like they had been painted on to her expansive rear if not for the bunching above her wool-lined boots. The top was a tight fit, with the belt being more to keep her belly under cover than to make the coat fit. As Ruby waddled out of the dorm room, her thick thighs rubbing together, she also noticed both sides of her hips brushed against the door frame.
'Heh, guess I might've overdone it,' Ruby thought to herself as she adjusted her fake beard and red and white hat. 'Oh man, am I even going to be able to walk after all the food tomorrow? Eh, that's a future problem.'
Ruby collected her first sack of presents and made off towards the dorms for her first delivery run. Fortunately, with her speed semblance, her run was much quicker than anyone else in the school would have been able to do. Unfortunately, it wasn't as quick as it used to be, back before she took on much larger and much rounder proportions. The couple of cookies and most of a glass of milk at each dorm room certainly didn't help Ruby's speed. The second and third runs got gradually slower and slower as Ruby got fuller and fuller. She was still so proud of herself for handling her cookies and milk so well, even if a small number of the rooms had left, of all horrible things, oat and raisin cookies and skim milk. Still, she soldiered on with her final delivery run. Her semblance enhanced sprint had been replaced with a waddle of impressive speed, but it had definitely slowed down from her breakneck speeds earlier in the night. The impending sore stomach, both from reaching capacity and from being constricted by the costume's belt, was beginning to rear its inconvenient head as she reached her final delivery.
As the milk-and-cookie laden Ruby returned her delivery sacks she lumbered back towards her team's dorm room with barely an hour to spare before sunrise. Her packed belly sloshed and bounced ahead of her, threatening to break free of her belted coat.
Soon, Ruby arrived, nearly out of breath, and quickly headed for the bathroom so that she could escape her confining costume and slip in to an almost equally confining set of pyjamas. Her winter pyjama shirt had well and truly given up on her, leading Ruby to wear it open over her summer pyjama tank top, which was only really useful for maintaining decency, as her belly, even when not packed with a school's worth of cookies and milk, poured out below the hem of the top. Even the sleeves barely fit her, being skin-tight around her flabby biceps and appearing to be a hair-breadth from bursting open at all times. Her pyjama pants didn't fit much better, as her belly hung over the tense elastic waistband and her thighs had begun working on small holes between the two, partly from slowly tearing seams and partly from even slower holes caused by friction. The skin-tight fit over her ballooned rear was another issue, but the pants still, by some miracle, fit enough for Ruby to not consider buying new pyjamas, even if it was at least partly stubbornness and partly optimism regarding her ability to fit it properly again relatively soon.
As Ruby filled her bed and drifted off into a food-coma induced slumber, her heart was lifted by the thoughts of her fellow students' reactions to her work and the holiday cheer it would bring with it. A slightly more selfish side to her had to admit that the mountain of cookies of all type was also a major bonus to the night's work, even if it would be a long road ahead of her to work it off.