Just explaining some bile mechanics and how to be efficient with it. This guide is not meant for beginners. I expect you know some basics when to use bile like saving it for running events or critical situations.

Some of these are obvious but it's worth listing most

• Bile effect duration is 20 seconds
  
• Commons are attracted to the area where bile broke
  
• If other infected is biled commons attack it
  
• If the hit infected was special also other specials attack it (except boss infected)
  
• Bile break resets random horde timer (random hordes happen at random intervals between 90-120 seconds)

It might not seem like it but there is huge difference between throwing bile on the ground vs on some other infected. The obvious one being that zombies attack biled infected. But there are more differences.

One being that when infected is biled commons won't attack you at all even when you get in their path. As long as the biled infected is alive of course. The other difference is a lot bigger. When biling an infected you attract all the wanderers in the area + if there wasn't 30 of them the remaining spawn up to 30.

On the other hand when you throw bile on the ground without hitting other infected all the wanderers in the area will run to it + a horde spawns. That means if there are 30 wanderers alive those will run towards the bile + 30 zombies are added to the spawning queue (30 commons can exist at given moment so the remaining are added to the queue and spawn when free spot opens for them). Not very good and 99% of the time you won't be able to kill all zombies before bile ends.

But basically when an infected is biled same mechanics are applied as when boomer biles a survivor.

Not a good situation. But it's not that bad situation when everyone knows what to do next. Your goal now is to cease firing on the tank or setting him on fire. Remember zombies won't attack you now even if you are in their path. Make the tank throw rock and let zombies surround him and beat him. He is basically stopped. That only works when he is not on fire or being fired at. With survivor bots not very feasible. In the meantime while tank is biled you should have pipe or molo ready. If you don't have it there still might be one around or maybe propane, oxygen tank or gas can. You should use one of these items right before the bile effect ends. If you do it sooner the upcoming wanderers that spawn may still run to you and be annoying.

Before I even start I am not talking about throwing bile on tank behind the corner and waiting till he dies. That's boring if you have only one tank maximum per chapter.

Two biles will almost certainly kill a tank if you know how. Of course it requires all teammates to know what to do so not really a strategy feasible in random public game. Always someone that will shoot at the tank and make the strategy meaningless. Even if you write don't shoot the tank. Can't blame them though. Biling tank is most of the time bad idea because of bile scarcity in some maps. This strategy is certainly not the best way to kill the tank but it is fun (at least for me).

First bile throw goes on tank. Second bile goes few meters next to the tank so it doesn't cover commons but covers tank. Tank has for some reason very big radius for bile breaking and covering him. Try to experiment yourself with what this radius is.

Idea to make this guide was kinda spontaneous and done under an hour. So it could be written better probably. If you believe some information is wrong and want to refute it don't comment with just some anecdotal evidence.
Also these are not strategies you should just go on and try in a public game, everyone in the team must know what to do. Demonstration videos were done in expert difficulty in my mutation with realism base mode so will work the same in realism.