In the north of England (UK) they sometimes describe someone (or
something) as a bit "twanky", "twankie", or
even "old-lady" if they are not so quick or clever, especially when it comes to use of technology.
i.
e. someone who isn't able to use a mobile-phone, or a DVD
player might be called a twanky. If it's the device that's at fault, e.g. an old out-dated phone, then it would be the device/phone that would be twanky and not the person using it.
I
don't know where this colloquialism originates - perhaps it's a reference to Widow Twanky.
The best way of describing it would be to say that you can use 'twanky' anywhere where you might say instead "my granny could do better".