Piss switching is a simple technique to increase the fire rate of slow firing weapons like the Shotgun and Rocket Launcher. Switching to a different weapon after firing these guns allows you to cut off it's "reload" animation and fire another gun when you would normally not be able to.

Piss switching is simply using the piss button instead of switching to a different gun. Tapping your piss button immediately after firing a weapon will immediately switch the weapon into itself. The fire button can be held down while doing this to make sure you're firing as fast as possible.

A comparison between the fire rates of the Shotgun and Rocket Launcher with and without piss switching can be seen below.

Have fun killing ♥♥♥♥!