There was a comic strip about a slave in ancient Egypt that hit me like a religious revelation, the whole idea of being a slave - or owning one, by then I was enjoying both sides of the fantasy - was suddenly intensely exciting. And it didn't have to involve any kind of sex, or even a lot of pain, just the idea of being under that kind of total control

This is the exactly the sort of thing I used to do, except I was always the slave, never a Mistress. Riding crops were usually involved in the fantasy. It wasn't a comic strip but I had a couple of books. It evolved into a sexual fantasy as I grew up.