Blown-in cellulose is damp enough for it to cling together until you get the drywall up.

The following was copied from Fine Homebuilding

"Sloped roof assemblies can be insulated with a wide variety of insulation materials, including spray foam, fiberglass batts, or blown-in cellulose. If you choose an air-permeable insulation like fiberglass or cellulose, most building codes require the roof assembly to include a ventilated air gap directly above or directly below the roof sheathing. If you’re installing spray foam, the roof assembly can be unvented.

Air-permeable insulation should be protected by a durable air barrier on both sides of the insulation. The top-side air barrier is usually some type of panel forming the bottom of the ventilation chute, while the bottom-side air barrier can be drywall, OSB, ThermoPly, or rigid foam. To ensure a tight air barrier, the seams of these panels should be sealed. It’s also important to caulk the joint between these panels and the kneewall top plate.

Make sure that you install enough insulation to meet or exceed minimum code requirements. The 2012 IRC requires at least R-30 in climate zone 1, R-38 in zones 2 and 3, and R-49 in zones 4 and higher."

"The top-side air barrier is usually some type of panel forming the bottom of the ventilation chute."

This is key to avoiding problems down the road.

Thanks guys. I'm having a really hard time visualizing this.... Do you guys happen to have any pictures?

http://www.oldhouseweb.com/blog/how-to-insulate-a-finished-attic/

More pics

Typically a baffle is installed to vent the roof deck and insulation to correct R-value goes under that. Correctly placed vapor barrier, towards interior in cold climates, towards exterior in warm climates. Spray foam is its own VB.