I main support. My favorites are 
In my opinion 
is the worst AD Carry in the game, until you can sneak into a teamfight late game. Today I was third pick, locked in , fifth pick locks in without any regard for bot lane synergy at all.
I cannot support this champion, and I'm convinced he's unsupportable.
Who should I play to support and why? How should I play in lane? Aggressive or passive?
Aggressive. Very aggressive. Twitch has built-in poison DoTs. They detonate Leona's sunlight passive. Until an ADC hits high AS, DoTs are a strong way to maximize Leona's passive rewards without requiring her to space them out. Her stuns can also help buy Twitch enough time to gain max stacks of his passive.
Twitch was very popular in S4 and was considered a top-tier adc by certain pro players due to his surprise mechanics and DoT+burst. He's just not that great in the current meta, but it's best to play tanky/CC champions such as Leona/Thresh/Braum. Janna or Karma are decent as well since Twitch can walk up with shield and get good trades without taking much damage.
Anyone who can keep people from diving on him. So, Janna, Nami, Leona, and Braum are real good, and he synergizes well with them.
Janna's shield while he's stealthed helps him win trades.
Nami's movement speed passive and little balls help him do more burst from stealth.
Leona's passive is proced by Twitch's poison, and she can counterengage if he gets all in'd.
Braum can leap to him and protect him with his shield. Also Twitch's rapid attack speed helps proc Braum's passive.
shaco... why they will synergrate perfectly they will suck togather :) and either enter the fight stealty or leave it stealthy
Zilean was the best for support Twitch. Have you ever heard of the "Stealth Bomber" video? It's the best thing ever. You drop a Q on Twitch, he goes invisible right into the middle of the enemy team, and BOOM! It has to a Zilean with tons of AP though, so like S3 mid zilean. :D
