It'd be really great if you give a little bit more information on this. Do you have any particular pet in mind? Or do you enjoy the feeling of being a pet?
If you are into a particular animal as pet play, you can get tasks accordingly. For example, if it's a dog, you can have a leash and a collar. Can have a cage or a place similar to it. You can can also mimick their gestures and made to show the affection as they do.
On the other hand, if you enjoy the feeling of being a pet, then tasks can be assigned accordingly. Eating from a bowl, collars and leash. Cages. Having a separate place or pot for bathroom activities.
So a bit more information can help in formulating tasks better.
Cheers.
Devil