So far six audience members have stormed out midperformance of the Broadway show “You’re Welcome America. A Final Night with George W Bush,” the comedian Will Ferrell’s lampooning of the 43rd president, according to those keeping count at the Cort Theater. But they haven’t been leaving after a particular Ferrell quip.

They’ve been standing up, instead, after the projection of a supersize photo on the backdrop of the stage. A photo of a penis. Specifically, as Mr. Ferrell (who plays President Bush) leads the audience to believe, the president’s penis. Except that’s not quite right.

“It’s an anonymous but age-appropriate public domain Internet penis,” said Adam McKay, the play’s director. “We went on the Web and got a penis.”

“It’s not the president’s penis, as far as I know, and Will is 41, so we weren’t going to use his,” Mr. McKay added. “What I do know is that the photo gets one of the great shrieks of delight from the audience, and it’s also the one moment that is followed by people walking out.”