Well I'm not from Austin - don't root for orange either, but I do like the Tshirts that say 'Keep Austin Weird' when I see them....
Here it is -- wasn't hard at all -- ran up and down the stairs a few times to see if it would drift upward towards my waist or shift or bunch and it didn't ...next step is to try it out next time I get on a horse or run.
Fabric I used probably cost $3, took me 30 minutes and $4 bag of dove chocolate. Not bad. 1.jpg 2.jpg
I have my flip phone inside it in the first photo - it didn't bounce at all while I jumped around and wiggled and jiggled. Sorry for the blur - my mirror was a bit dirty and reflecting it all.
I think I just saved myself $25!