1. Try febreeze or starch them. I dont like both, but it helps against bad smell and puts other smell on them.
2. Fresh air them over night. Or even longer, if needed.
3. Put them in the freezer over night. Kills some of the stinky bacteria.
4. Give them a soak.
5. If nothing helps, fucking wash them and stop stinking next time.
How long have you been going without a wash? Maybe you can already wash them safely. If the denim is not only broken in but really worn in, most of the creases/wrinkles form again in the exact same spots where they used to be before washing.