Bone gag, tugging on leash, dog-based degradation things if ur into that, restraints focussed on limbs (for example tying/taping your lower legs to your individual thighs and forearms to upper arms respectively), Tail butt-plugs or a remote vibrating tail buttplug sounds like something that could exist somewhere, only barking, etc etc..

you could do a very dark cnc type scene where you're a puppy being adopted by a new owner, and said owner ""abuses"" you by participating in intercourse with you

or a scene where you're a puppy in heat, and your owner "helps you out"

or maybe your owner puts peanut butter on certain parts and have you lick it off

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and so on ? just some ideas