Start with a karada. You can manhandle her, move her around, lots of control, yet her arms and hands are free, she can get up and walk around, you can tether her but she can unleash herself in an emergency...

She just needs to see you play and playing for a while, without coming to harm, before she will feel at ease being helpless should something befall you. That will happen sooner if you and she play up to, but not including, her total helplessness. Then, a year from now or so, you can incorporate bindings using quick release snaps and other escape mechanisms. Eventually you'll get her back where you want her.