Shart is a portmanteau of shit and fart, and refers to a fart that results in the soiling of ones pants/underwear. It was mentioned by the character played by Philip Seymour Hoffman in the movie Along Came Polly.
To protect against sharts, one could place a Manpon (usually a bunch of toilet paper) in one's underwear to maintain cleanliness. Manpon is a portmanteau of Man and Tampon.
中文意思，通俗點說，就是放P崩出來shi啊 fen水啥的搞到褲子上很惡心的
這個詞就是shit 和 fart的合並詞
出處是壹部叫做《遇見波莉》（Along Came Polly）的電影