What makes this such a perfect duo, is that once Twitch uses Q, Yuumi becomes invisible as well. So you can sneak both into line undetected and then both start ulting at the same time, creating near sure double kill situation, or forcing 2 flashes.

In addition, her Q is just good for pokingsince your poke options are limited. Also, she has a plnety of healing and sheilds for you to keep you alive. If you can, you should always go for this duo.

Important thing to keep in mind, your poison is dealing damage even without pressing E. You may remind your jungler of this, to not steal his buff by this passive damage. You still should help him with buff tho, and also dragons!

On the lane, you should first focus on farming and wait for your support to create some openning. Once you have lvl6, you should recall for first buy and sneak into lane behind the enemies. Wait there for your support to engage and instantly follow with your ult.

A thing to look after, is that your poison on enemy champions makes turrets focused on you, so try to stay out of their range and only push once the enemies are not present.

For me, mid game starts when first turrets are falling. Once you push yours on bot lane, thats when you should go full ambush mode. Look for any sort of options how to sneak behind enemy line and once fighting breaks out, focus the weakest ***tes of enemy backline. Do not focus tanks unless necessary!

If you have it, use huricane to quick farm sidelanes and enemy jungle camps, but in general stick near your team. Despite some safety of your stealth, you have no dashes for quick escape.

Your full power comes once you have first 3 Items finished. Then you should be able to unleash hell any time the opportunity shows.

Bad news, your late game push is not as powerful as some other ADCs has, but you can be pretty effective on objectives. Try to contest dragons and Baron to get advantage for your team and to have easier time pushing the enemy base.

In case of teamfighting, even tho you will be much stronger now, still seek the ambushes. You are one of few ADCs with this option so its easy to completely surprise enemies, they may not even notice you and be fully focused on already present threats.

Last sneaky tactic in late game that you can use is backdoor. Once that nexus is without turrets, you can always try sneak in with your Q and win the game by yourself.