As an adc in this situation, I often tell the team I am pushing out bot and to not engage, but the moment i leave the enemy forces an engage and kills them 4v5. If I stay in mid, we just dance around not engaging while the tower takes damage.
I'm starting to think as an adc I should be the last person to leave to push it out
Make someone get a 
and have them stick it right under turret at the unattended lane before grouping mid. Ask your support or a 
to build one by mid-game.
P.S. : You can see in my match-history that I absolutely practically swear by the !
If you're grouped for a teamfight, it might be worth losing a tower to win the fight.
Otherwise, a good way to prevent this is to do a laneswap. Switch lanes with your midlaner if they have waveclear, so they can shove the lane harder than the enemy adc can push it (to protect the tower, mind you). Unless you're against an assassin midlaner (or Annie/Lissandra), the support should be able to reasonably protect you.
Firstly if you have someone with 
they should be the ones to go clear the lane if its available for use. Otherwise, If you have someone with a near global ult (examplts being 
) then they should go shove the wave.
Also, depending on the tower, it might be best to just let it take damage/get destroyed so you don't have to weaken your teams presence in mid.
You could also try to force an initiation to try to get some kills or at least force the enemy back to base or something.
You are right though, as the ADC you are the last person that should be going to clear a big wave in another lane if there is mid lane action going on.
From my understanding, around mid game or so, the ADC basically switches with the mid laner so that they (the ADC) have quicker access to pretty much any objective on the map in the event a fight breaks out over it.
I think the first thing people do wrong is that they push out too far when they go to clear waves. What you want to do is just clear the wave under the tower, and then get a small wave going. How it works is the smaller the momentum your wave has, the longer it takes to get to the enemy tower, but the larger that wave is when it gets there. The ideal situation is that your wave only has a single minion advantage, so by the time it gets to the enemy tower, it is very larger and can easily be used to take a tower rapidly. The practical application of this is that you probably need to clear the wave immediately under the tower, then one more and a bit to make sure that the wave is functioning properly and that their split pusher doesnt just immediately come back down to apply pressure. This probably should be done by someone who has tele or better waveclear than the adc, but the adc can do it fine as long as they dont start pushing. A good way to look at it is if your the adc, you should never push past where the next tower is. If your first tower is down, you really shouldn't push past where it was. If there first tower is down, you shouldnt push pas where that tower was.
Pretty much yes. whenever The enemy team sees your ADC (usually your primary source of DPS in a fight) leave during a siege, that is the number one signal to bum-rush the tower outside getting a pick and killing one or more champs.
If possible, have your top laner (who should have TP) or any champ on your team with a global/semi global teleport ability be the one to push it out. Alternatively, use a global ult like Gangplank's or Ziggs' to clear the pushed wave instead.
all have global/semi global teleports and are all decent at pushing a wave, some actually being exceptional split pushers.
