Pettanko

The pettanko is a Flat Character. Literally.

The meter ^{[dead link]}(NSFW) has to start somewhere...

"Well, excuse us for being flat!"

—Etna and Flonne, Disgaea

This might actually bother her if she is already considered childish and prone to tantrums, so the sore spot becomes endearing. Occasionally, she is proud of that flat chest as a way to appeal to a certain demographic of guys, although real fans in practice make a distinction between merely being flat-chested and actually being underage. Nonetheless, it is very useful in creating a character who looks younger than she actually is.

Also known as "Delicious Flat Chest", or DFC, a term apparently coined by Image Boards.

Now has its own song.

Contrast, obviously, Big Breasts, Big Deal (and its subtropes).

Note: This is a fan-speak term, not a trope. Do not use it as such. Doesn't mean it can't still be used, but just not as a trope.

For actual tropes with examples, see A-Cup Angst and Petite Pride.