when you tie your wife to the side of a docked tug boat and munch on her va-jay-jay for hours on end while making the noises "nom-nom-nom" and "toot toot"
This is a dutch tugboat when your buddy isn't up to fucking the hooker you just paid for. So you take him sailing out to sea via the tugboat. Don't forget to bring him into the harbor (her snatch).
After getting the escorts up to the room and a fifth later, my Jedi Protoge was not up to it, so I persuaded him with a dutchtugboat out to sea.