to be fully dependant on another. one who is completely incapable of being to complete the most simple day to day tasks without screaming for help.

To have a Tantrum, Mental turn, Spit the dummy

To screw something up royally, such as break or crash an expensive piece of equipment.

Often used in 'pull a wilkie', a common phrase meaning to crash or break something.

Also note, 'wilkied': An item that is broken, often because someone 'pulled a wilkie',

Commonly used when talking about expensive pieces of equipment.