What to use for skim coat?

[spicegirl]

New to this forum and just wanted to ask to be sure as I'm still starting up.

What's the better option for skim coat? Do you use sealer or primer or both? I figured many people haven't been agreeing on the same thing. Imma do 2 skim coats after I sand the textured ceiling so I need ya help on it.

So what's the best one for this situation? TIA.

 

[UnderDog]

I use both, bcs it's more effective. but whatever you do, just make sure that the surface are clean before applying the sealer of primer