I think it is one of those phrases that means different things depending on the context/person. I always think oral sex when I say it, but I know other people would probably say it is the act of sitting all over the face and not necessarily oral. Some people might like the crushing powerlessness of it.

How loose is your goose?

I am assuming a giant sculpture of a cow that is made out of butter. Probably for a county fair.

Umm…can I have some candy?