Using AP is a very fun and unique way of playing this champ considering that he is suppose to be AD or jungling. when using AP Udyr it is always best to start off a battle by using Phoenix Stance, by doing this you are able to ignite everyone around u in team fight. Because Pheonix Stand is Udyr's main move as playing AP,this makes him very good (Farmer). try to get as much buff and kills in jungle when ever you can while holding down a lane with your partner. If durable enough or not focused in a team fight AP Udyr can deal Massive amount of area damage do to Phoenix Stand. Good Luck and have fun.