The guy says, "Sister, I've never sold alcohol to a nun."
She says, "It's for the Mother Superior, she's constipated."
So he sells it to her. Later that night, he walks out, and there's the nun on the stoop, with the empty bottle, drunk as a skunk, singing and laughing.
He says, "Sister, for shame. You told me the bottle was for the Mother Superior's constipation."
The nun says, "It is. She's constipated,
Spoiler:
