After a heavy night of drinking at the local bar, a drunk stumbles into a Catholic church and slowly makes his way into the confessional booth. There, the priest patiently awaits the man to begin his confession.
After a few minutes of silence, the priest politely taps on the window... nothing. The priest taps again and this time clears his throat a bit... still nothing. At this point the priest begins to lose his patience and bangs on the window.
Finally the dunk yells out... "Ain't no use knocking, there ain't no paper over here either!"