i've had some experience in this area, although limited due to my mistress living about 3 hours away.
whilst talking online, i was to be naked and i wore a dog collar. rather than having a glass of water on my bedside table, i had a bowl of water on the floor and at night, whilst i slept, i had to attach my collar to my bed with a chain. both myself and my mistress got a lot out of it, she allowed me to cum but i wasn't allowed to touch myself, since dog cannot do that. instead i had to hump a leather boot that was provided for me. she also trained me to lick my own cock, which i managed to do after some contortion!!

the few times we were together i wore my collar 24 hours a day, aside from when i was being washed, and ate scraps and drank water from bowls in the kitchen. she talked about taking me outside to pee, but we didnt get that far. i fantasized about being bred by her parents large dog, but again, we didnt get far enough to take that route and i dont think she would have wanted to anyway.

i would love to have another chance to take on this role someday.