From NEMO: Once the pad is fully dry, store your pad outside of its stuff sack flat or loosely rolled in a cool, dry place. Leave valves open during storage. 

https://www.nemoequipment.com/cleaning-repairing-and-storing-your-sleeping-pad/

Superusers do not speak on behalf of REI and may have received
one or more gifts or other benefits from the co-op.