Once it's dry?
Well you could play the asshole shithead evil dealer game and spray it with kool aid or whatever, but then I'd never talk to you again.
When it's still in the growing process, things that cause excessive bud stretch/fluffiness are:
-not enough light
-sativa influence
-heat stress
-light leaks during dark cycle
-not enough carbon in the soil and/or atmosphere (point behind CO2 enrichment and watering with carbohydrates=increase yield/bud mass)