Inflation is the expansion of a character's body, or part thereof, in a uniform, disproportionate way, usually through the introduction of a substance.

Overview

Inflation involves a character's body, or part thereof, expanding, due to the introduction of a medium, usually a gas like air or helium, or a liquid like water or juice. The specific appeal of inflation is the shape of inflated parts, which is usually abnormally round and smooth. This is in contrast with other forms of expansion, such as Gaining weight, Breast expansion and Butt expansion, which involve an exaggerated but believable distribution of body volume.

This article will seek to be as extensive as possible, however there are difficulties with writing articles about expansion and inflation fetishes on Pixipedia, due to the asymmetry between Japanese and Western users' understanding and categorization of works involving expansion.

Types and Categorization

Western fans of inflation categorize inflation art very finely, by both the substance involved and the part of the body being filled. However on Pixiv, the tags used to categorize inflation art are coarse, and combine many of what Western fans would consider separate categories. As a result, Western artists often opt to use a more active Japanese-originating tag, and then tag the specific content in a free-form manner.

Additionally, on many image boards, "inflation" either literally assumes or is overrun with "cum inflation" content; an assumption which persists in some manner on Pixiv.

The following will attempt to match Pixiv tags with Western terminology.

Full body

膨体 Swollen body - Specifically body inflation. This tag crosses over with Change of status more than 膨体化. Limbs are sometimes left proportionate, or may be sunken in, rather than inflated as well.

膨体化 Boutaika - The most consistently used tag for inflation of the entire body, including limbs.

風船化 Balloon transformation - A crossover tag with Object transformation or Change of status.

太膨 Bloated - Used very commonly for expansion of furry characters, although human characters are present. In general, leans towards Gaining weight.

Part-specific

ボテ腹 Bloated belly - Any increase in belly size will end up in this tag.

膨腹 Belly distension - Focuses on the belly, and contains a large proportion of cum inflation, object insertion, vore, and stuffing. More recently, this tag has come to include content that Western audiences would consider close to an *inflation* interest, but this tag remains very broad in scope.

ブルーベリー膨体 Blueberry inflation - See article.

Related/Accessory Tags

浣腸 Enema - Less related to injection for the goal of inflation, and more to its original medical purposes (or for its own sake.)

ホース浣腸 "hose enema" - More specific to the realm of "inflation through the anus" than the general "enema" tag.

水道浣腸 "water enema" - Tag specifically translates to "water enema", and bleeds into both non-inflatoin and inflation content.

空気浣腸 "air enema" - Self-explanatory, although sometimes used as a general air inflation tag.

破裂寸前 "just before bursting" - Inflation images with a sense of pressure and/or urgency, implying an imminent rupture.

腹パンパン "belly filled to bursting" - Same as above but for belly inflation in general.

There does not appear to be an active, dedicated tag for inflation-induced bursting, but the 破裂 Explosion tag is sometimes used for this purpose.