Firstly, this technique requires the use of the Genjutsu: Sharingan. The opponent is caught in the illusionary world created by the user, and the victim is tormented with the sensation of having spikes driven through their limbs, taking away their body's freedom. At the same time, the physical pain accompanying the illusion reveals that the greatest use this technique has is torture.
As seen when Itachi used it on Orochimaru, it has been proven that one of genjutsu mastery may use this genjutsu without eye contact.
Orochimaru described this technique as a type of "Temporary Paralysis Genjutsu" (金縛りの幻術, Kanashibari no Genjutsu).