Sonny tells Calogero he is going to lend him his car to pick up his date so he can give her the door test. This was at a time before there were automatic lock doors. To give her the door test, Calogero is supposed to unlock and open the car door for his date and then close the door for her. He must then walk around the back of the car and look through the rearview mirror. If she doesn’t reach over and unlocked the door for him he has to dump her.
Sonny says, “If she doesn’t reach over and lift up that button for you so you can get in, that means she’s a selfish broad and all you’ve seen is the tip of the iceberg. You dump her and you dump her fast.”