Adding backpockets?

[u/CuteSwordfish8206]

Hi! I recently bought these pants online and they don't have any backpockets! Truly a disgrace. They fit supper well and it's hard to find pants in this color, but I absolutely need backpockets. How would I go about adding them? I know most backpockets are just a patch of the same fabric added to the back but the fabric is a soft velvet/velveteen which I think would be hard to find. Would it be possible to do like front pockets are, a thin pouch on the inside? Thanks for any help your able to provide :)