Thats a difficult injury to treat on the spot
The Red Cross/St Johns courses teach the use of pressure, torniquets are supposed to be a big no-no as you can loose all circulation to the limb
How ever, if its completely pissing blood you arent going to to stop it unless you can clamp off the artery, the armed forces have gone back to using torniquets in cases of a severed main artery
The civvy first aid course wont tell you to use one though because of the litigation angle, if its squirting blood on your face pressure wont stop it though
Its your call guys