Yeah treats don't work because if he dose it once and then knows I have the treats he loses interest and just wants a treat lol, he did do it one day a couple of times but he won't do it now.
Someone told me to put the dummy in his mouth and take it out and then praise him, but the bloke who told me also catches 20000 rabbits every time he takes his whippet out so I didn't really want to try that hah