Titanic

When a male takes a female to a public bathroom and has sex with her, ending with him giving her a pearl necklace. He then proceeds to the urinal, removes the blue urinal cake and throws it on the pearl necklace. Resembling the "Jewel of the Sea" necklace from the movie Titanic.

Guy1: "Dude, where did you go?"
Guy2: "Oh, I took that girl to the bathroom and gave her a Titanic"