I'm low tech...I just stuff a couple of poop bags in my pocket or jacket pocket.
If I'm wearing a dress, I tie them around the leash before heading out...(yes, I have become that person who walks the dog in a work dress and sneakers, LOL).
Hmm, also, when does he chew it up? We hang our leash by the door on a hook, Rumo has never gotten his mouth on it as far as I know?
Rumo ~ rescue shepherd/husky mix