Reddit mentions of Earth “Easy-SEAT” Camp Stool w/Steel Legs, Comfortable Nylon Fabric, 3-Legged Outdoor Fishing Stool, SIT Anywhere!

A guy on my courses always had a spare canteen that he filled with jelly beans. Best de-stresser ever in the 5 minutes you get between taskings.

Also, I'm not sure what kind of EX you're doing and what you can take, but we found these to be incredibly useful and they strap onto a ruck very easily.

On a more practical note, take lots of socks. I mean lots and lots of socks. When your feet are soaked from sweat or a swamp, no better feeling than a fresh pair of socks. If you haven't already, get a pair of SWAT boots or similar so you don't want to amputate your feet after a day in the field.

One of my personal favourites was to always carry a ziplock bag of really tough beef jerky in my tac vest. Has a similar appeal to dip, but without the mouth cancer and I found it helps keep energy up during longer marches.

I never really had a problem with any of the shit we had to do during exercises, it's all kind of fun when you have the right mindset, so most of my "hacks" were just ways of being more comfortable during downtime. That's really good for keeping your sanity, and I think it applies to everything in the Forces :)

Finally, if they gave you one of those shitty old canteen cups in your kit that are tin or something and poisonous to drink from, consider surreptitiously replacing it with a steel one.

As others have said, they are camp stools: http://www.amazon.com/EASY-SEAT-COMFORTABLE-3-LEGGED-OUTDOOR-ANYWHERE/dp/B00AKHSVUE

http://www.amazon.com/EASY-SEAT-COMFORTABLE-3-LEGGED-OUTDOOR-ANYWHERE/dp/B00AKHSVUE

That's not the exact stool I have but it is a similar concept.