2 flavored mystery swirl
When a man eats a womens vagina out and then bring the cum from the vagina to the anus and gives the girl a rim job, thus creating two flavors, that of the cum, and that of the rectum.
Last night i was eating out my girlfriend and my tongue slipped to her ass hole and i totally gave her a 2 flavored mystery swirl.
Mystery swirl
The random spluge-stain you see under a UV light (generally on a motel bed).
Brendan: "We stayed at the cheapest motel; it had a mystery swirl on the bed!"