That is ADORABLE! I love it :)
It looks like you're using food rewards - all for that - but another way to teach them to roll over or lay down with clicker work is to spray them with a hose so they'll roll, then click and treat right when they lay down and using a verbal cue like "lay down" when you see them just about to drop. Repeating this a few times.
Either way you and your pony are adorable! I love watching people enjoy their ponies