DIY: Thundershirt for dogs

I have recently come across this in Facebook. Unfortunately, I didn't see the author so I can't credit him or her. This is something really useful for us, dog owners. Not too sure if it will work for cats though.

You can make this 'Thundershirt' to calm your dog(s) in storms and fireworks! I haven't tried it yet... will do it as soon as I could find a spare towel :-)