Two little boys go into the grocery store. One is eight years old and the other one is five years old. The eight year old grabs a box of tampons from the shelf and carries it to the register for checkout.
The cashier asks, "Oh, these must be for your mom, huh?"
The eight-year-old replies "Nope, not for my mom."
Without thinking, the cashier responded "Well, they must be for your sister then?"
The eight year old quickly responded, "Nope, not for my sister either."
The cashier had now become curious "Oh. Not for your mom and not for your sister? Who are they for?"
The eight year old says, "They're for my five year old little brother."
The cashier is surprised "Your five year old little brother?"
The eight year old explains: "Well yeah, they say on TV if you wear one of these, you can swim or ride a bike and my little brother can't do either of them!"