Luke, how did you detail this window?

In this video how did you detail the windows (at 5:05 in the video) above? I’ve been wondering about this, but have heard to use special tools. Here you use a Ninja and I know it leaves plenty of water on the window. Do you just hit it with the Fixie Clam and are done or what?

just wrap a towel around the end of your pole and detail like that.