There’s a nice little farce called “Garremont Gaiden” posted at the BE Story Club.
The premise is that an evil cabal of women has developed a dart and air gun delivery mechanism for a breast expansion formula. After being hit with the dart, the victim has just a few minutes to find a new outfit before her breasts swell substantially. Multiple exposures to the dart can cause a woman’s tits to grow to absolutely enormous proportions.
Our heroine is Dr. Moxie Russell, a chesty genius with blue hair tasked with stopping the breast enlarging rampage of the conspirators. Tragically, Moxie is repeatedly shot during the course of her mission, causing her already generous breasts to become larger, and then a bit larger, and then larger still, et cetera ad absurdum. Not that I’m complaining.
Anyway, there’s a free sample here. (You should totally check it out.)