Definitions by Lomey and Tukey

Dunderfunk 

This is the technical term used when using the lavatory to excrete personal baddies from the rectumal area, the resulting excretion will leave an undesired layer of water on the buttocks and thigh area.

When you go for poo the water bounces up and hits you bottom opps. This is naturally called Dunderfunk.

Dunderfunk by Lomey and Tukey January 12, 2011