You can help confirm this entry by contributing facts, media, and other evidence of notability and mutation. Yiff is a slang word used in the Furry fandom used to refer to sexual activities and furry pornography. Over time, it began to be used as a term for sexual activities, and furry pornography. One of the earliest examples of the phrase comes from a Sabrina Online comic shown below. Though some say that it dates back even further to the early 90s.