Hahaha!! Everything you just described is my Bella to a tee. To a TEE!!! Even after spaying! I think it's normal. My parents' chihuahua (RIP) used to hump other dogs--and she was spayed as well! Like the others said, it's very likely to be a dominance thing.
__________________ Mary  Mommy to:  Bella  Rocco Teddy  Missing you..  Lily, Chaos, & Jasmine <3 |