This occurs when your father, or another man, or woman with a dildo, or your mum with a dildo, entered your mothers vagina while she was pregnant with you which led to the impression of the penis/dildo being left in your soft skull. This then becomes a feature of your skull. It can be useful for storing food or as a flower vase.
'Look at that big whole in his head mummy'
'Don't stare, hes got cok in de head syndrome'