"Underfluffies" is a term used to describe the genital area of a character with feathers. This area is often depicted as having a soft, downy texture. The term is used a lot for avian characters, but also extends to feathered dinosaurs, avali, and other feathered species.

To be given this tag, the avian pictured must have this part of the body exposed (such as lying down, from a raised tail, or the perspective is a low-angle view), be visibly non-convex (flat underfluffies are fine), and contain fluff of some kind. See also post #1654593 which started the meme of underfluffies.

post #1421410