Welcome to the guide of being an OP Udyr. First things first... beware your tiger stance is going to drain enemy health faster than a blink of the eye... I know that is bad. Most people prefer to be a tank and do 0 damage whatsoever, and leave their enemy alive longer... maybe cause turtles kill things slow. Well this build, you're a Tiger.

This build is more full of pro's but it does include cons...

Pros:

Ganks never fail (level 5 boots)
Super insane damage
Tons of kills
Destroy turrets in seconds.
Able to kill dragon and baron earlier.

Cons:

Squishy (but you kill them too fast for it to matter)
Crowd control owns him (if you get your bear stun off first, won't matter)

By the time you get blue and red, you should have enough money for level 5 boots. This is important. Rarely you will miss a gank with such speed.

Dash in with bear for the stun, then release your tiger stance to dps them down... if they are full health, Using exhaust at this time will guarantee no escape from your tiger stance.

Boots of mobility ensure kills upon ganking without enemy getting away.

Phantom dancer will bring criticals and faster attack speed to your tiger stance to ensure kills. This item helps you to lifesteal with turtle for more attack speed.

Infinity edge adds damage to your tiger stance which has a 150% attack damage bonus along with more powerful crits in your tiger stance. (Enemies will Cry themselves to sleep after your bear stun knowning whats going to hit them next - Tiger bites :)

At this point you can build your own way.

I reccomend phantom dancer, but if you're dying for life steal at this point and turtle stance not good enough.. Buy a bloodthirster, it will also make you do tons more damage in tiger.

This skill sequence is important... Tiger can kill blue by himself.. leash makes it easy as pie.

After getting tiger you get bear, you can imediately gank after this point. You can go to enemy jungle knowing they are about to go red as most junglers do after blue... Sit in the bush... Bear stun them and then tiger bite their life away.

Phoenix is an okay skill... but you will not need it at all with how much more damage tiger does. Honestly I find it useless... Go through full games never using it.

Keep turtle up high after maxing tiger so you can : Steal life, and have a shield to survive epic escapes like turrets or any ability.

Give this build a try before hating on it. I did not go into much detail for all you should really need is the item build. Follow the order, gank when enemies pushing too far, and Win.

Thank you and Enjoy an epic build.