Wait for a break in his rush and ask him about this "dark" thing

When he finishes collecting cash and stamping some hands, you lean in quickly.

"Sorry," you say. "But what do you mean, when it gets dark?"

He grins at you. "You never been here for a black-out night?"

You shake your head.

He chuckles. "I won't ruin it for you. But definitely keep me in mind, later." He gives your ass a swat. "I wouldn't mind seeing how much you can handle."

Then he goes back to work, and you're definitely dismissed.

Though you have to wonder about the whole "how much you can handle" thing...