Means to 'act like you've got a pair of testicles'
Is an insult to imply that the man has no balls in the metaphorical sense (that they are a total wimp).
Often used by males and females alike, in women to display power and in men to shame the other male.
Always directed towards a male unless you're taking the piss.
Woman: Bloody hell (insert name here) act like you've got a pair will ya!