Just give it a lick...

I have an acquaintance—let's call him Sergey. He’s a welder par excellence. When it comes to metal and welding, he’s the go-to guy. He’ll tell you, explain it, and show you how it’s done.

We were standing outside, smoking and chatting about random things, when a guy who shared his workshop bay walked up to us. He was carrying a small metal ingot.

"Hey, Sergey. Listen, do you think this is 55-grade steel or 45-grade?"

"Just give it a lick."

"What do you mean, 'give it a lick'?"

"I mean, just lick it. Like this—with your tongue."

The guy, never taking his eyes off Sergey, carefully gave it a lick with the tip of his tongue.

Sergey: "So?"

"Fuck if I know."

"Fuck if I know, too."