Yiff

Sex between furries. See Furry. Most commonly used in the form 'Yiff in Hell', indicating to furries that they or their sexual practices are not welcome in a given locale.

Good places to yiff include FurryMUCK, TapestriesMUCK, and, on the evidence, despite all claims to the contrary, /tg/.
Jesus fuck Christ, how do you even know this shit?