Hump

Hump

Humping is when an individual mounts and thrusts their hips. Sometimes it is simply referred to as mounting. This is a natural form of action where the male takes an active role.

Male animals instinctively begin to hump around the time of sexual maturity. They may direct this behavior toward other animals (most often dogs, but also other species), inanimate objects, and yes – of course – people as well.

This is often one of the behaviors owners are attempting to stop when they neuter their animals.

While performed more often by males, female animals sometimes hump as well. In cases where a female puppy develops in the uterine horn between two brothers, she may become masculinized to the degree that she humps and even lifts her leg like a male to urinate!

References

http://beastiality.club/beastiality-club-extreme-animal-sex-content/the-encyclopedia-of-zoophilia/