New way of hailing a cab

Little Fella: Press this button and the taxi will come ( said with a straight face whilst pressing his belly button)

Mummy: You sure a taxi will come if you press the button. What colour taxi do you think it will be?

Little Fella: I think it will be a white one ( he loves the Mercs cabs)

There you go, a brand new way of getting a cab. All with the press of a button.