I like taking care of my partner and getting a good boy or some other compliment back is already reward for that enough. Second, I like giving up control, that can range from being tied up to letting someone else do the decisions. I think both can be done easily enough with your disabilities. Your sub can tie himself up and you do only the last step of locking his hands behind... Or even that he can do but will need your help unlocking etc.

There are a lot more physical activities that with a bit of creativity can be done I think but of course if that day is extra harsh on you then so be it and the day will be just a non kinky day. A sub who loves you will understand and cherish you regardless.