(My mother told me this story, which happened to her as a cashier when she was in college.)

My mom: “Are you going to pay for that other Coke?”

Male customer: “What Coke?”

My mom: “… The one in your pants?”

Male customer: “That’s not a Coke, that’s my penis!”

My mom: “If that’s your penis, I am going home with you right now!”

Male customer: *slams coke on the counter and walks out*

Related:
Grannies: Gotta Love ‘Em
Dads: Gotta Love ‘Em