Einen Im Tee haben

I love it when you come across a bizarre phrase and it turns out to be an idiom. Was just reading GuteFrage and someone posted

'I know you can smoke tea - but what kind is best?'

And someone replied

'Wer Tee raucht, hat einen im Tee'

He who smokes tea has one in tea

Eh?

So googled "einen Im tee haben" and one of the top results was gute frage (of course- it is the source of all knowledge on the Internet)

Was bedeutet "einen I'm tee haben"? 

 Turns out it means to be drunk and one answerer conveniently listed other ways of saying it -

"er ist besoffen, blau, hacke, dicht oder wie du sonst sagst..."

Thanks again gute frage - an invaluable resource not only for tea smokers but also for german learners!