To be used whenever a mate makes a stupid and simple mistake that is wholly obvious to all other than the mate who made it.
Origin
T- I quite fancy a small car, like a macan but electric
M - oh have you thought about an electric Macan?
……
M - What drink are you having?
T - I fancy a beer, larger than a half but not as big as a yard
M - You mean a pint
MG - you electric Macan that one