Sneaky secrets

My dad and I were out to dinner last night just the two of us. We'd been out running some errands and to round out a night of shopping at the sporting goods store we went out steaks and burgers. I asked dad if I could have dessert and promised that I wouldn't tell my mom if I did get something. I got an ice cream sundae and said "don't worry dad, after I finish the ice cream I'll eat a french fry to cover it up."