Trundle adc is not optimal but if you wanna have some fun and ruin people's day as being the big troll king this guide will teach you how to do it. If your support questions you just follow this guide and prove them wrong. This guide will talk about how to play Trundle adc in all stages in the game. This is just a guide for you to have fun with a troll bot laner but hope you will enjoy and see you on the rift.

In laning phase against a ranged champ you will be punished a lot for csing so try to stay back and if you do get punished you can use Trundle's life steal and dorans shield to get your health back along with his runes. You want to focus on csing but if you have an engage support such as rakan or nautilus and they hit their cc don't be scared to go in and use e to immobilize them and then w in. If you have an enchanter support like Yuumi or Morgana don't be afraid to just charge in because they provide you a ton of utility and always try to set up ganks for your jungler.

Ahead/Even: After you got your turret with your support remember Trundle gets turrets really easily since he can q them. If you are ahead you should go mid and push mid as much as you can along with your support and midlaner to get mid turrets which will pressure their jungler and getting more prio for objectives like drags.
Behind: If you are behind then stay bot and farm until you have gotten your second core item that is not boots and you have gotten first bot lane turret then head mid and help your mid laner and always be prepared for teamfights and don't run off on your own even though you are kind of tanky you should still play it a little safe always make sure someone is there with you since you are not building regular trundle.
Mid Laner:If your mid laner is behind and you are ahead suggest that they switch lanes with you but if they are ahead group up with them.
Cheeky Kills: If you see a squishy champion by themselves you can definitely get a pick on them with your e immobilizing them and w to catch up to them then you should be able to kill.

Behind: In the late game you want to really focus on objectives if you are still behind rely on spilt pushing since Trundle takes tower really fast with his high attack speed and can also escape dangerous situations now that you have some movement speed items and you can probably 1v2 and 1v3 depending on how much items you have since you should be getting some decent lifesteal.
Ahead: If you guys are ahead use your lead and hard push mid exert as much pressure as possible and when there is an opportunity go for Baron and look for the end.

Since you are Trundle you are still pretty tanky because of your passive and insane lifesteal and attack speed so don't be scared to go up in front and ask your support or jungler to peel for you try to go for the squishy champions since you delete them really fast so try to proc your BOTRK as fast as you can and just charge right in but you should definitely not charge in when you have no peel. Your support is what makes Trundle adc a true monster just let them pocket you and you will 100% dominate the other team in teamfights. Also if you ever see a good teamfight opportunity since you are Trundle you can also act as an engage for your team. Make sure to use your R in teamfights for extra durability.

Core Runes: You wanna use Hail of blade for the dps and the domination tree provides a lot of omivamp and life steal for Trundle. Resolve secondary is very necessary since the two runes work really well with Trundle and still gives him some durability despite him being an adc.
Other Runes: Take conq when you are going against tank heavy comps and if you are looking to have fun and just run people down take the run it down trundle runes which will provide you a lot of MS.

Starter Items: For items you wanna start mostly with Doran's Shield for the sustain since you are going against a ranged enemy but if you know you want to play really aggressive then go dorans blade for better all-ins.
BOTRK: BOTRK is necessary to Trundle adc since he definitely has trouble against kiters like caitlyn but if he is able to proc BOTRK they are good as dead since now he is able to just run them down and kill them easily make sure to really use your e and w to immobilize them and catch up so you can get a pick.
Nashors: Nashors is also essential and is buildable since Trundle adc is all about his attack speed and lifesteal and his R scales off of ap so Nashors definitely works.
Tiamat Items: he Tiamat items are also essential to trundle as it helps with his lack of AOE you can go either ravenous or titanic it really is just your call.
Mythics and Other Items: For mythic items you will mostly be going Trinity Force since it provides you with a lot of attack speed and you will be relying on your q for damage but you can definitely also go the other mythic listed on this list. The other items listed here are situational and the optional items are items that work but isn't optimal you can go them if you wanna have some fun.
Boots: For boots mostly you will be going something so you can be a little for tanky and you're not particularly looking for more dps since you have enough already but you can still go Berserkers if you are really ahead.

Bad Matchups: Trundle does very badly against adcs who can kite him really hard and supports with long ccs and heavy pokes in these match ups just play it safe till the mid and late game comes around.
Good Matchups: In good matchups with champions such as Jhin you need to take advantage and when you see an opening try to go in since they are immobile and can't do anything against you so you smack them to death with your club or you can take very good trades. If they have a tank engage like Rell or Leona use your E on their bot laner in the back and rush them since you probably won't have much like killing the tank.

Engages: Trundle works really well with heavy cc and engage champs like Leona and Nautilus since they are able to go in and hold them there which let's you Trundle to be able to go in and slow them even more
High Utility supports: Trundle also works really well with these high utility supports like Yuumi and Soraka since it gives him more sustain and makes it so he is able to make good trades against the enemy adc also making you able to go in a lot faster and easier
Poke Supports: Trundle doesn't work really well with poke supports such as Vel'Koz and Zyra since they don't give him much oppurnities to go in and also doesn't provide much peel for them since Trundle is a short range champ he can't really go in and finish them off since they can just back off really easily.

You want to first catch them with e them use w for the movement speed and other buffs that come with then go in and beat them down with your q and r if it is up.

At the end of the day Trundle adc and this guide is just for fun. Trundle adc really utilizes his high lifesteal, attack speed, and movement speed where he can easily chase and club down any adc. He works really well with high cc and peel supports. If you are looking for something new and interesting and fun then try Trundle adc where you will show who the real troll king is but I promise you definitely won't troll if you follow this guide now go club and chomp on the players in the rift.