Dancing: What Kays said. Clicking on them won't do any good. You need to click near the area, then hover your hand around the action. He should catch on. Or, you can attach his leash to someone who is dancing.
Once they've learned, there is no way to force them to dance, though you can increase their chances by tying them up near dancing villagers. It helps if they are good so they don't get the urge to destroy the villagers or whatever he's tied to instead.
Field food: Teaching the creature this isn't hard, but I don't recommend doing so. Because of a glitch, when the creature eats from the field he will vomit because the batch of grain registers as an inedible object...
If you still want to teach him, do something similar to the above. Click near the field while a farmer is taking from the field. Try attaching his leash directly to the farmer, but don't let him pick it up, just have him watch.
