Public Toilet

A man enters a public restroom. As he takes down his pants, and sits on the toilet, he hears a voice.

"Hi!"

"Hi!" replies the man.

"How are you?"

"Good!" he replies again.

"What are up to?"

"Well, I'm taking a..."

Upon this, the voice says,

"Listen, I'll call you later because somebody also keeps answering me from the other stall..."