At game time, Cougar fans show their support by making the "Cougar sign," made by folding the ring finger of the right hand toward the palm.
The tradition dates back to 1953, when Shasta I, the presiding cougar mascot, lost a toe in a cage door on the way to a game.

https://www.ttu.edu/traditions/gunsup.php#:~:text=The%20%22Guns%20Up%22%20sign%20is,fingers%20to%20form%20a%20gun.