Yes, that is just what it appears to be!

I swear, I was just down the hall in my room, with the door open, even! It was only five minutes! Suddenly, I heard the sound of water being splashed around a little too vigorously to be the tooth-brushing sounds I expected. So I went to check it out.
Let's just say that they didn't get wet from running their toothbrushes under the sink.
When I walked in I was really tempted to scream, but instead, I walked away, picked up my camera, and documented.

While I was gone, they decided that it wasn't enough to dunk their heads, they wanted to try baptism by immersion. Fortunately, they are too big to get all the way in. But, Brigham was really pulling his foot out of the pot when I snapped this shot.

After documentation was taken care of, I had them strip down and hop in the tub for a little one-on-one with some soap and hot water. While they were scrubbed, we had a little chat that went something like this:

Me - "So guys, what kinds of things go in the potty seat?"
Boys - "Potty"
Me - "What else?"
Boys - "Toilet paper"
Me - "What else?"
Boys - (turning greenish and getting quiet) "poop"
Me - "And, where did you just stick your heads?"

I don't think we will have this particular problem again.