The May'boq was a Klingon term that related to the battle fever they experienced when fighting. It was noted as being a distant and more primitive part of their thoughts which sent their emotions soaring as well as filling their bodies with an almost electric energy. In time, this experience passed with a normal focus returning to the warrior in question though it was noted that once the may'boq had faded, it was hard to return to their normal duties. This was because the Klingon in question still heard the faint murmur of blood in their ears and left them charged for combat.
In 2372, during an infiltration mission onboard a Dominion starship, Worfs experienced the may'boq when he and Major Kira Nerys had to expose their position in order to save the life of Snoct Sneyd. The battle fever aided Worf in combating the Jem'Hadar soldiers that were onboard the vessel. (DS9 novel: The Heart of the Warrior)