Project chickens onto Trump tower. It’ll hit the news, he’ll see it, and it’ll push him into another debate. His people can’t control him. The might be able to manipulate him to some extent (e.g., “you don’t need to debate again, you won. What else is there to say/do? All you could do is lose. Leave it on the W.”). So, if you goad him enough, hell agree to another one.