Frosting Finger
Giving someone the Frosting Finger is when a person removes their finger from an anus, and having noticed an amount of fecal residue, inserts said finger into the mouth of the anus owner.
I gave her the ol' frosting finger for her birthday, and she threw up on my brother.
Jack Frost's finger
The act of filling up a rubber glove, freezing the water inside it and then fingering oneself with it
Last night I tried out the Jack Frost's finger it felt great