I heard that dry shampoo is meant to be used after shampooing.

I didn't know either, but I recently found out that dry shampoo is something you spray on clean hair after shampooing...

I sprayed it in a hurry before washing my hair, and while it looked clean on the outside, it felt greasy to the touch, so I wondered if I was using it correctly. Apparently, it's meant to be sprayed on clean hair to prevent it from getting too greasy!