I wash both. I think the shower helps your hair to not tangle as much as sink
Outside in the rain with all of the juices and berries that are near by on the tree!
Nah seriously in the shower
Shower--haven't used the sink since I was a little girl (laying on the countertop on my back while my mom washed my hair).
Shower keeps my hair going downward - so no tangles. Also, I've read the horror stories about ladies whose hair went down the drain in the sink!