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Breast Expansion
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Breast Expansion is a trope typically found in Hentai and more extreme Ecchi series. Breasts suddenly begin to grow larger in size, sometimes with little or no explanation.


Breast Expansion is the idea of unnaturally rapid breast growth in women, in some cases going from a flat chest to very large breasts in a matter of seconds. In entertainment media, this is usually used for either comical or sexual purposes or, in some cases, is simply part of a transformation and is given much less focus.

Anime & Manga

Usually used as comic relief in various anime and manga franchises, Breast Expansion typically happens to one or more unsuspecting female characters with little or no warning, usually resulting in hilarity at the expense of the characters involved.

Depending on the anime/manga, the expansion of the female character's breasts can have several different results, anywhere from using their new-found bust size in order to attract the attention of male characters to the totally insane result of being carried away high into the skies due to their "ballooning" busts.

During accelerated breast growth, characters generally react in one of two ways: either freaking out in a most spectacular fashion or finding the growth stimulating and pleasurable. For the most part, this depends on whether the trope is being used comically or sexually.

Notable Examples

  • Manyuu Hikenchou Revolves around this concept. Chifusa has the ability to "steal" the breasts of other women, adding their volume to her own.
  • Fairy Tail In Chapter 486 and Episode 302. Brandish uses her Command T magic to play around with Lucy's breasts, before setting them back to normal.