Shampoo-ING

I never understand this language. It's almost as silly as English sometimes.

"Eh, William, are you done in der?" Guy knocks on the bathroom door.

"One sec Guy."

The door opens. William is washing his hair in the sink.

"Can I 'ave dat when you are finit?"

"Sure. When I'm done--" William says, pointing to the shampoo, "--Shampooing?"

"Yes! Exactement."

Guy walks to his room and tells his other room-mate Bernard he's not quite ready to go out yet, "Ben, un moment, j'attends pour le shampooing."