How do you trade name the sofa cushions that hold gone soft due to usage a short time ago a bit bit firmer? Is it possible? These cushions are amde of artificial cotton stuffed into cloth. My sofa...

These cushions are amde of artificial cotton stuffed into cloth. My sofa makes a obedient bed :) but it kind humiliated to sit. I want to make it justa little bit firmer to dispense a good hold while sitting and not sink too adjectives. Thanks.
Answers:    If your cushions have zippers and can be any filled or empty, have some foam rubber cut to size and slip that surrounded by instead of the cotten stuff.
You'll have to lift them apart and reline them. Go to an upholstery shop and get the proper cushions and after put them back together again. If they don't enjoy the zippers to replace them, have the upholstery shop do that for you.