How to play vs Morg as supp!?!

^Topic i dont know nothing about counter a morg

As Leona bait her shield with a small engage. Just when your cd's are up again, engage at the enemy adc.

Most important, and obvious, dont get hit by her Q :)

just force the shield on her with something small and then just go on the other target

I recommend you Karma. She has a very nice ability to dodge her q + her insane amount of poke is almost a free lane vs her. I kinda forgot the other counter to her. Brb

EDIT: o yea sure how can i forget zyra. Janna very good vs her aswell.

Youll need a lot of Trade Potential and a lane that doesnt relay on hitting cc. You need to keep track of her Cooldowns because without her 10-20 second cooldowns shes worthless for her ADC.

Bait out her shield/take the binding if your ADC cant avoid it and then heavily focus her ADC.

You wanna play Lulu, Soraka, Sona and Thresh against her, since she has no real counter in Lane but these Champions perform well regardless.

Play someone that can break her shield (say annie or something, she also has instant stun which shield can't block), just don't run the typical Thresh/Blitz since counters op

One Simple Trick - Dodge her Q.
Maybe focus her, only when her ADC is bad.

I didnt really read what the other guys said so I'll just give you a little overview.
First of all, which sounds pretty basic, well which actually is pretty basic, you should be in a good position the entire time, one wrong step could basically lose you the entire lane and make your late game a pain.
Try to stay behind the creeps all the time, also you should avoid standing in brushes which you are not 100% about that they are not warded. When you know her Q is on cooldown (11 seconds on all levels) try to put a little pressure, but only if you have vision on river and tribrush.
You can try to put her in sticky situations with forcing her to use her E (23/21/19/17/15 seconds cooldown) when she used it you just gonna wait for you stuff to come back up since its most likely on a lower cooldown then her E and just engage on their ADC.
Post level 6 though, you should try to stay out of her ult range (600 I think not too sure) or atleast in the outer area.
I think I covered the most important stuff. Possible picks against her are Caitlyn, Ezreal, Tristana, not just because they all have an escape with lower cd than Moragan's Q but also because they can attack out of high range.
When it comes to supports I cant provide any personal experience but according to statistics Braum and Karma are the only supports who win more than they lose against Morgana.

I hope I could help you with that lil overview, when you liked it gimme a thanks mate :)
Good luck on the Rift!

You will need to stay behind minions if you cannot gain bush control. Make sure the bush she's in is warded and prepare a solution if she decides to flash ult.

DoTs or fast poke spells could help to make morgana casting her shield.
And stay behind minions, dodging her Q.

dodge the q & get attack speed as ad carry

It's not really difficult, when she use her black shiled on her adc she is the more squishy player on le lane, she hasn't any escape and she is afraid of cc. Morgana Hasn't so much HP without items so you need to kill her at the start of the game, hten it's easy win on the botlane ! Care about her Ult and zonhya she loved to use this

dodge q
look out for her spell shield so you dont waste your CC on the enemy that is spell shielded
look out for her ult,a knockback(vayne E or trist ult or alistar W) can be very helpful

Leona for the Win !