Here was their team: Yasuo, Shyvana, Leblanc, Shaco, Caitlyn. I was jinx.....
Look at the amount of backline... even if I somehow survive the back line I'll get blasted by a sniper ult :(
How do I play against that in team fights ? I could snare 2 of them at a time but the other 2 back liners were still able to 2 shot me.
DeathBurst2 votesThat's definitely hard, there is no simple magic, but there are a few details that you can keep in mind. The absolute most important one is: get vision!! You need to stay out of range of all this assassins, but for that you need to see them coming. LeBlanc/Shcao dashing/blinking through a wall and flanking you is your first concern.
Stay in rocket form, hit whoever is closest, you don't care who, just hit someone and stay safe, and back off as soon as they try to go in for your ass. Also, buy a Guardian Angel at some point (not sure, I'm not an ADC main, but I'd say something like 3rd item, after IE/Runaan). And depending on the rest of your team, you can go for semi-defensive items as 5th/6th item (Maw, Sterak, Frozen Mallet, ...). If your Tanks/Supports are doing their job properly and manage to peel for you, that's not needed, but if the rest of your team is also squishy damage dealers, then it's probably best, your team will have enough damage anyway.
U R Good At Game1 votesI was even fed af too. I left bot lane 4-0-1 with a 30+ cs lead on Caitlyn only to get 2 shot by the shaco, LB, Yas backline.
venomous frost1 votesstay far back out of range untill they blow their engages.
That team was made to kill you
XPhantomBusterX1 votesI don't know. Just stay in rocket form 24/7? If they get close, just run. You could also get a 
xD. Maybe you could build more defensive items. You could also try to prevent team fights. If your support was half way decent, he could've peeled for you and blocked the caitlyn ult.
GeminiRune1 votesI can concur. is usually my fallback item when it comes to being a major threat target on the enemy team. When it comes to just kiting that without much peel, it's not fun. And it's not like you can just go completely unconventional all the time. I had a game where I built 
on 
(the Maw/Steraks tandem nerf wasn't applied back then) and despite it making me "tanky" enough to stop them from treating me as a primary threat, I feel like I lost out on actual hard carrying. The comp you had however would probably just rip health to shreds though, especially in the current itemization meta.
U R Good At Game1 votesOk, thank you all for the help! <3
Maiziea1 votesLb and shaco: can't really do much about these 2 on your own. If they go for you, you just stay out of their range and force them to focus someone else or make them over extended while your team kills them. Rely on your team to peel for you, if you are the carry they will focus you so as long as you can bait them into your team you don't even need to hit them and you can still be the one to kill them without even getting an assist, granted this is hard to do it's in my opinion very effective it just requires a lot of knowledge on how to play the other champions.
Yasuo and shyvana: you're jinx... Dodge, kite, put down your chompers. The only issue is the windwall because it forces you out of position if you want to continue dealing damage.
Caitlyn: shouldn't be an issue until you've dealt with the other 4 and when you have dealt with them, shouldn't be an issue, adc fights are pretty straight forward. If you somehow do have to deal with her before the other 4 one of you two are really out of position. If that's you then you most likely threw the teamfight and that's your own fault, you deserved what happened and better luck next time :). If it's Caitlyn that's out of position just kill her with your team, she shouldn't live longer than half a second and if she does you can probably blame that on your teammates, though there's no point in actually harassing them about it.
I'm not sure what elo you're in/ how good you are but that's about what you should do in an equal 5vs5 team fight. Low elo teamfights are messy and unreliable so don't worry too much about losing them and just focus on your mistakes. hardly anyone has decent positioning so take advantage of that because as an ADC positioning is SO important, if your team isn't afk during the team fight you can often kill LB/Shaco/Yasuo with positioning and baiting alone (probably wanna use your chompers against all their dashes tho :P).
There's also GA that can really take away their motivation to kill you :P but once you do stay around your team because if you get caught you just made that item useless for the next 5 minutes which is a waste of gold. Personally not a fan of GA on ADC because I'm a carry and I have decent positioning, if they kill me I deserved it and I'm not willing to give up the damage in most of my games.
I hope this helps you, I'm kind of rambling on lol.
PS: back line=the ones that stay in the back (adc/control mages ect) not Shaco, Yasuo or LB :P.