I don't know about the cushion but I have a special chair I use for sewing, quilting etc. It is called a knealing chair - there are several different styles - mine looks like an office chair but the seat is tilted slightly forward and there is another cushion type seat for your knees to rest against - its supposed to keep you upright and in correct position for your back - I also had wheels put on mine and I love it. I will post a pic if you are interested.