A Japanese slang, for one's attraction to younger males, or those who appear to look younger, as told in story format, or magazine series. Uses the Hentai format, as its vehicle for presentation.
In more Western Cultures, this could be akin to those who are attracted to Twinks, young males eighteen to twenty two.
Usually an anthology series.
Early roots, are based on a sort of erotic clone of the Baker Street Irregulars, in which a younger detective is attracted to an older one, who then develop a relationship.
Based on the 'young' looks and 'features' the younger man involves himself with the older detectives cases, and older detective, erotically.