Upon reaching climax (usually by HJ or BJ) a man sticks the tip of his still wet penis into his partner's ear. Similar to the manor one would give a "wet willy" with their finger.
Usually deemed disrespectful.
Tom was a real jerk. He gave Bonnie a wetsherman after she blew him.
To put one's penis between one's legs & rub against one's bumhole. Tada.
Jane was mortified when she came home to her husband hoovering the house whilst performing a Rusty Sherman and crying out in a high pitched voice `I'm a lady!'