How to play blend pose animation onshoot?

Hi, i wanted to know how do i make a blend pose animation play when i click left mouse?
if you look right here

you will see when the left mouse button is press which is called “shoot” it fires a projectile, ive tested it where it plays montage that works but i just want the upperbody of my character to perform the animation.

If you look right here

this is the blendpose, how do i make it where when i click left mouse in blend pose it plays a animation? maybe a function like “isFiring” something like that, cause right now i have it where when the character is aiming which is part of the movement when right mouse is clicked is fires the blendpose in spine_02, however i want the animation to play when left mouse is click, i just need some help with that thanks for your help.