hmmm it would be either of two fantasies based off between fantasy (unrealistic) and fantasy that's at least maybe plausible.
The plausible one:
I'd have a remote controlled vibrating dog dildo in my ass, and some sort of ball shocker on my cock. I'd be wearing an extremely padded diaper and put into a latex animal suit where I'd be made to be someone's pet.
The more detailed but unrealistic fantasy would be if the popular pokemon game were done real life in a kinky fashion. This fantasy was inspired by this fanfic I read from prometheusdragon. I would love to be a trapped in a growlithe suit on all fours with the shock collar so I could only speak like that, and participate in trainer battles where one pokemon wins either by sucking the other pokemon off to cum, or by cuming in their ass instead. I'd love the training and the battles. It combines, oral and anal sex, bondage, latex, and pet play while still giving me a bit more intelligence then a pet. It would be my ideal fantasy. Living like that in costume 24/7.