work for the student council, they give you money every time you tutor/do swim classes with someone and you unlock the math minigame with the fat chick, though you need max perception skills to see it fully
That worked a lot, but learned it s pretty useless for now
she's also not really fat, she's more curvy cuz of a lack of stomach. Who knows, maybe a future sex update will prove me wrong
edit: Saw a screenshot of her in her swimsuit, that girl chubby, def gonna grind her story now