[subby999uk]

You like him to exercise so here's a task for him.
Get him a dildo gag, something with a large dildo to stuff his mouth with and an even larger one on the outside that he can pleasure you with.

Lay on the floor and get him to position himself between your legs with the dildo above your pussy, put something under his hands to raise them up a few inches.
Now get him to start doing pushups so he's fucking you with the dildo as he does them, you can set him a target of how many strokes you want to feel and encourage him to go faster with threats of punishment and of course punish him if he doesn't reach the target.
You should do this several times a week with your demands increasing as his strength and stamina builds up, the ultimate goal is that he will be able to fuck you to an orgasm as he performs pushups for you.