A Shiny Nickel is a sexual favor usually given by a girlfriend, wife, or an escort (prostitute). To give one a Shiny Nickel the female must first lather the males' anus with semen and vaginal fluid. Then she must "shine" his anus with her toungue until squeaky clean.
Man #2: Amazing! After the movie she gave me Shiny Nickel in her Grandma's bedroom!
Man #1: Fucking Epic...
Example two: "I gave him a shiny nickel, and he gave me a 20 dollar bill!"
Example three: "I gave him a shiny nickel asking for a 20 dollar bill, and he gave me a blowjob in return. What the hell?"
Example four: "I gave her a shiny nickel asking for a blowjob, and she gave me a kick to the balls. I hope I can still have kids."