Sarah,
I had to laugh at this. Your little girl is perfectly normal
. My two bitches used to do it to each other and when they were both in season, you had never seen anything like it. They couldn't decide whether they were bitches or dogs. They were humping each other constantly.
Its most like a domination thing with her sister. As her mum and sister visited her in her home, she was just showing that she was top dog.
Don't worry, cockers can been funny little things and don't beleive anyone who says bitches are better than dogs. They both hump anthing that goes at some stages in their lives.
Have fun with your little girl
Sandie