When in the process of giving oral sex to a male, a finger is forcefully jammed into the receiver's rectum without prior knowledge.
When Biggie G was blowing Johnnie B, he decided to surprise him with a Turkish Eye Opener to get him to cum quicker. Johnnie B screamed with delight after the initial shock.
Gaming: When an initial hit/confirm is landed, presumably leading to damage .Prominent in the fighting game community or any games that would involve combat.