Add my voice to many others on this particular fantasy, from both sides of the coin (being a switch rocks sometimes). In fact I'd say pet play/animal transformation is one of my main interests. I've had an ongoing pet play with a Domme online for over six months now, and if we didn't live so bloody far apart we'd take it much farther. This includes for us collars and leashes, being naked on all fours, not speaking as a person would unless told to do so, eating and drinking from a dish, being trained and rewarded in the manner one would obedience train a dog (a subject I have a great deal of experience with going back to early childhood), wearing a tail/buttplug, sleeping in a cage at first, then earning a doggy bed, then eventually if I behave well to the extreme, being allowed to sleep on/in the bed on occasion. Coupled with all variety of sexual acts, of course.

We also both have beastiality interests and she'd like her male dog to "breed" me, which I'm not opposed to trying either. In fact I'm quite curious just what that would be like. As an aside, despite the fact that with people I much prefer women at about a 90%/10% ratio, in terms of my beast interest I'd say it's about 99% towards the males. Make of that what you will.

I'd also be more than slightly interested in having a girl as a pet from the Dom perspective. It could go as far and as often as she wanted it to.