He picks up a needle and pokes it with that. 

The needle can also overshadow the light, though the light's big enough that it can't be fully overlapped, so it's always still glowing while needled.

"Can everyone do this where you're from?"

"If they learn how. Lots of people don't."

"But they can all learn?"

"That's my understanding."

"All right, what do you want."

"That's a really complicated question. Should I not have shown you if I didn't have a plan for how I was going to fully explain it -"

"Of course you should've shown me! I'm really glad you did! Is it rude where you're from to ask for a price on something someone isn't sure they want to trade?"

"Not as such."

Pokepokepoke "I want you to teach me."

"I'm thinking about it. I'd like to."

Poke poke poke poke bounce bounce bounce.

Giggle.

He gets some lenses and starts looking at it through those.

She sneaks another light in bright green into existence behind him while he's doing that and waits for him to spot it.

"Ooooh!" He has a lot of these lenses to look through at both of them.

Also some long crystal sticks to poke them with.

The crystal is transparent enough that it can refract the light and throw it all over the place for a split second before the light winks out.

-oooh.

This is cute. She replaces the light with a wave of her hand.

Then he'll try with more crystals.

The crystals don't always dismiss the lights on the first try but they usually do it within just a few.

What about a mirror?