Okay, so I'm confused, or maybe Blossom is?? lol. Blossom started humping her brother a couple of days ago, and tonight she kept mounting him, and trying to hump him all evening. I didn't know females humped, I thought only male dogs did this behaviour. Dozer does not do this, and never has, and Blossom has just started this. They are both 19 months old, and are spayed and neutered. Why would she start doing this now?