2 things: as you press the red button down 1) lift up and back 2) consistently make sure that the contact areas between canister and stick are dust free (I blow on them everytime but an air can would probably be healthier). These 2 things have kept me from pulling my hair out and throwing the thing in the trash :)

I found that lifting up and back, after depressing the button, works well for me, and keeping all the connecting parts dust and dirt free.