Thank you everyone for your kind comments.

The Thundershirt has had a very calming effect on Yazi. I noticed a difference in her anxiety level after putting it on her almost immediately!
It's designed to wrap it around their bodies and then adjust the velcro just enough to put a gentle, constant pressure around their chest.
It's the same effect as swaddling a baby with a blanket to calm them down. I'm so relieved the thundershirt has had that same effect on Yazi!