That is kind of interesting....
And since I was curious, I did a google search on the new term used in the description....
Dōjinshi (同人誌?, often transliterated as doujinshi) is the Japanese term for self-published works, usually magazines, manga or novels. Dōjinshi are often the work of amateurs, though some professional artists participate as a way to publish material outside the regular industry. The term dōjinshi is derived from dōjin (同人?, literally "same person", used to refer to a person or persons with whom one shares a common goal or interest) and shi (誌?, a suffix generally meaning "periodical publication").
(from Wikipedia)
Teenage Mutant Ninja Turtles TMNT doujinshi - Usagi Yojimbo + x Leonardo*
Item Title: Yo! I'm Over Here!
Produced By: Namigashira
Format: Doujinshi
Language: Japanese
Page Count: 30 (0 novel)
Size: B5
Date Produced: 2009.05.03
Condition: Used - Very Good
* Legend:
Character x Character implies a romantic/slash relationship between characters. Character + Character indicates a friendly relationship or familial tie.
Unfortunately, I am not into what passes for fan fiction lately, so I will pass on it.