The frosted unicorn is the act of taking an alaskan pipeline and strapping it to ones head. Such as performing the unicorn sexual act but with an alaskan pipeline. Tie the alaskan pipeline around your head to look like a horn. you then ram it in someone's but until they climax and while they climax you neigh like a horse.
Jane: (to friend) I told Bob I refused to recieve an alaskan pipeline but he was very persistent so one day as i got out of the shower he ran in to the bathroom with a poop condom tied around his head an pleasured me with it yelling that he as a frosted unicorn. I was surprised to find out how good it was!!