Jacket has more backbone than I have

[ICantBelieveIDidThis]

As per title, really.

In a charity shop, I bought an unusual, densely woven, cotton jacket with a peplum 'skirt' running round it.

It was adjusted and washed and is now as stiff as a board.

The (American) washing instructions are fairly clear: gentle cool wash and no iron.

Anyway, the peplum sticks out rigidly at the back, giving the strange appearance of looking like I've caused the fabric to 'fly away' because of a massive fart.

I usually use white vinegar and Zoflora, but the jacket is so very dense, it feels like cardboard.

Just how in the world do I make it softer and more wearable?

Not sure but we definitely need a photo of the flying fart effect in order to advise

What's it made of? I'd try steaming it - just using steam from the iron whilst it's hanging up. Sounds as though it might have viscose/rayon in it. What happens if you try to scrunch it up?

Cotton.

It's almost like a thick denim

We need a photo.

Pics.

Did you tumble it?

More pics

No tumble dryer.

Iron it on the inside on a high steam setting.

You need to bash it about a bit to soften the fabric - I had a jacket like this and the point of the tumbling is to soften the fibres. Can you wear it for an hour or so and see if it softens?

Thanks for all your advice.

Am at work currently, will try the steam iron when I get back.

Stick something like a pair of trainers in the washing machine with it.
I don't normally recommend machine washing trainers but old ones might do the job of kicking the fart flap into submission.
Thanks for the photos.