The Sexy move, is a four turn trigger, most often something like R U R' U' but any sides may be used for the same sequence.
As a stand alone algorithm it has not much use but with a set up move or a few it becomes algs (conjugates). The shortest LL alg of them all is done like so using F for setup; F (R U R' U') F' (for F2L 9).
Arnaud likes the sexy move
In April 2008 Arnaud van Galen released a series of excellent YouTube videos entitled "Complete beginners 3x3x3 tutorial" within which he coined the phrase "Sexy Move" to describe the often-used R U R' U' trigger.
Techno MP3 track
In November '08 speedsolving.com member a small kitten posted a link to "The Sexy Move Remix", a techno MP3 track created by Vaughn Sulit featuring quotes from Arnaud's tutorial. This was soon followed by an accompanying YouTube video and a StepMania track both celebrating the Sexy Move.
Whilst the sexiness of the R U R' U' trigger may be disputed, the brilliance of the term may not!
I just use... Sexy Move... All you need... Is the Sexy Move... I just use... Sexy Move... Again and again and again.