'gin talking'

'That's all he ever told you?'
'After a few martinis in the lounge, he did say that he had created the breakthrough of the ages. I thought it was the gin talking.'

Thomas Tompion said:

This is quite a common expression.

Some people when they've had a few drinks talk all manner of nonsense. It isn't gibberish: it's comprehensible, but fanciful; not very closely related to observable facts.