Wiktionary
walk the dog
vb. 1 Take a dog for a walk 2 (context idiomatic yo-yo English) perform a trick where the yo-yo rolls on the ground, attached to the string 3 (context idiomatic lacrosse English) Perform a trick where the ball rolls down the shaft, and then is caught in the head of the lacrosse stick.
Usage examples of "walk the dog".
When dinner was over I helped her wash the dishes and walk the dog.
It wasn't quite time for Alexander to come home from school, so he thought he would walk the dog.
They cook dinner, they wash dishes, they answer the door, they walk the dog, they vacuum the floor, they make the beds, and water the roses and virtually anything else you ask them to do.
Obviously these two had volunteered to walk the dog so they could sneak some cigarettes.