What to do with my 2 year old? what is the appropriate "punishment"?

While I was putting the clothes in the dryer, my son took a half a gallon of orange juice and went to the open window in the living room and poured the juice on the screen and window seal because "the dogs are thirsty mommy". Luckily I don't have carpet anymore. But you can imagine the mess. He has never done anything like this and he knows better. He knew when he did it that be was going to be in trouble because he came to me with juice all over him saying "now mommy don't be mad at me. Please clean me up". What is the best way to handle this? I made him help me clean it up, but he is still laughing because the dogs are licking the side of the house.