The act of plopping a sloppy/wet shit on the nipple and/or breast. This was originally created by the Germans, as an act of punishment. It is now known as an erotic way to pleasure the body.
Man #1:“Man, I could go for a solid shit on my nips right about now.”
Man #2:”I’m not feeling that at the moment, but I could definitely plop a nug”
For more examples, RE: Two Girls One Cup