ok, this is a weird question, but she never did this when she lived with me, she has lived with my friend for 1 year now, and she has been doing this since she got there, basicly several times a day she with sit with her back legs straight out and her front paws placed between her legs and she starts humping herself I have tried to figer this one out but to no avail. anyone have any idea what in the world she is doing and WHY? for more info she is a 9 year old spayed sheltie/BC mix.