Lewd-ish (weight gain)
A fantasy.
Being a maid to a very FAT and extremely generous Mistress. Every morning you bring her plate after plate after plate of delicious food, and then you rub her bloated belly as she settles down on her double-king-sized bed after a nice meal.
It brings a good paycheck and you also get all the leftovers.
And with a world-class chef in her employ, every bit of those leftovers is delicious, and you're absolutely encouraged to eat and snack on all of it.
And soon, you can't help but notice your own weight climbing up...