Come in - erotic short story

He has promised his mum to shovel snow and sweep driveways to earn some cash. He heads out into the cold air and knocks on the door of a big detached house. An older, but incredibly sexy woman opens the door wearing nothing but a dressing gown wrapped loosely around her body. She invites him in and her eyes reveal that she is much more interested in other things than having her driveway swept. They are eagerly undressing each other when they hear a key being turned in the lock downstairs...