Twilight, in an attempt to better fit her role as a Princess, accidentally curses herself with a spell that causes her breasts to grow to strain whatever bra she wears. After a few weeks of watching his mother-figure fail to reverse the curse, Spike decides to start loosening her bras to keep her from noticing the growth.

Day by day, the Princess of Friendship is becoming less mobile, more horny, and Spike is worrying more and more that he'll get caught.

Just another cup size and he'll stop... won't he?

A Twilight Sparkle breast expansion fic written in the form of letters back to Celestia.

Kinks: Breast Expansion, Hyper Breasts, Extreme Innocence, Lactation, Extreme Horniness

Commissioned by growthlover