We spent a lot of time doing this in January:
Christopher was helping roll out the pizza dough.
For a few weeks, he wouldn't wear pants.I struggled to put his pants on him one day, then went to take a shower. He removed the pants, then carried his pants into me, saying "Duh, duh, duh duh, DUH!" in quite the indignant voice and threw down the pants.
Christopher grabbed Ashlyn's doll and ran away with it, her running behind, screaming.
Later that night, when he again wouldn't put on pants, he removed his diaper and stood there, peeing onto the carpet.
Christopher colored on the couch with an orange crayon.
When we left the dentist's office, Christopher started walking into a HUGE, DEEP puddle. Fortunately, he stopped and turned around when I yelled, before his rain boots filled with water.
I have said NO more to him in the past month, then I think I have to Ashlyn EVER. I am definitely reminded of the forward from No, David! "of course, yes is a wonderful word, but it doesn't keep crayon off the living room wall!"