Hey,

First guide from me.

I just felt like sharing this build, as it's extremely fun & effective ingame.
I love watching them Teemos get oneshot :D

Pretty viable if you play it correctly.

Laning phase

You want to play passiv-agressiv very early.
Wha I mean by that is you try to hit a Q + an auto as soon as you can.
But don't take too much damage from it, cancel your move if you feel like you're gonna loose the trade.
Knowing that, you pretty much charge up your passiv while moderatly (watch your mana !) healing your ADC and yourself.

Teamfights

Stay between your backlane and your frontlane to be able to heal exactly the right guy when needed.
If you see an opportunity to place your Q + auto combo, DO IT ! You'll poke them to death.
Don't be too greedy though, place one combo and retreat in your backlane, repeat.
You'll win eventually if your team doesn't **** up.