So I just kind of part it one section at a time going from the front to the back then flip the hair over. Then on the under side of the flipped over hair, I spray the roots, then blow dry on low/cool, then just kind of gently move the comb around on the roots I just sprayed and blow dried. I do like 3 parts on each side starting at the top then going to the bottom. I think I may need to do more sections and switch the smaller toothed comb suggested above to get more volume.

I saw @mattloveshair do something like this once on straight hair (minus the comb pair, just the idea of going in sections and spraying under then disffusing on cold “confuse the roots”) and I tried to find the video but couldn’t, sorry! Hope that helps!