The President's Box. Lincoln was sitting on the right side, near the door. Boothe entered through the door you can see on the far right. The play was "Our American Cousin." Boothe waited for the line that got the biggest laugh in the play, "Don't know the manners of good society, eh? Well, I guess I know enough to turn you inside out, old gal -- you sockdologizing old man-trap." The laughter covered the sound of the door opening as Boothe made his move.