Student or Learner
"According to the expert I spoke (oh yeah, I called in the big guns on this one),heavy dreanking like this could be an indication of deeper issues." What does "call in big guns on" mean in this context?
It's an obvious military metaphor. When soldiers find their weaponry too light for present needs, they called in the big/heavy guns.
A similar metaphor, referring to more advanced military tactics and technology, is used in business when a manager deters interference from the authorities: 'You just get on with the project. I'll give you air cover'.