What do you say when a fellow library patron turns a corner and spots you, penis in hand, furiously wanking away?

“Oh, hi,” is what Leroy McFarland, accused public masturbator, came up with Friday afternoon when his illicit pleasure session at a Sioux City Public Library branch was interrupted.

McFarland, 44, “looked surprised” and sought to cover himself with his sweatshirt when the female witness spotted him, according to a criminal complaint charging him with indecent exposure.

A cop working at the library subsequently approached McFarland, who apparently kept touching himself after initially being spotted.