How can I disable shields while using axe and mace

https://reddit.com/link/1sbiobf/video/nvj9x5wb70tg1/player

As emberassing it is to say, I use a second mini keyboard with 3 buttons at my feet, there binded to the left click. When I go to axe and mace, I can only get it about 15% of the time. I go up switch to my axe, and left click the mouse and the keyboard at my feet at the same time and switch to my mace. What am I doing wrong? Am I switching too early or not timing my click properly because it's hard to time both clicks?