Furry is a sub-culture in which the "members" have some connection with anthropomorphics. This can be in many ways, as roleplaying,anthro art, fur-suiting, feeling they have the spirit or soul of an animal etc. Furries vary, they are male and female, come from all continents, all age groups etc.
Back to the stereotype. As I said, this is an incorrect view of Furry. Though this is not something all Furries take part in there are a small proportion who do so. Anything to do with sex in Furry is called yiff. In the '90s there was a sudden uprise of yiff art on the internet. Most of this has gone now, but this image of Furry remains.