Learn English – The expression “And how!”

Well, I bit the bullet and asked the guy what the heck he meant (imagine that). Turns out he was referring to the oft-quoted teach a man to fish proverb.

He also clarified that this is not a common expression, just an idiosyncratic reference he invented and uttered spontaneously.

It was first used as an interjection in the 19th century: “They marched, and I amongst them, to face the enemy – heads up – step firm – thus it was – quick time – march!”

Then, at the beginning of the 20th century, it began to be used adjectivally, as in: “He was always right on the job, and looking ‘heads up’.”

Then, around the late 70s, it became a noun, probably through shortening of phrases like “heads-up alert” into “heads-up”: “It is regarded as being a heads-up on a sale.”

^{Source and references: the Grammarphobia blog}