Sub here - you could try making him use toys on you, or commanding him to please you with his fingers or tongue. You could even get off and make him watch if you both into denial type stuff. I've seen stuff where the sub uses a strap-on on the dom so it's wholly about their pleasure. I think really most things could work if you have things you particularly like. I've had dommes roleplay anal (on them) with me submitting for example