Torres undergoing the ritual
The Ritual of Twenty Painstiks was a Klingon ritual ceremony. It was a component of the Day of Honor.
After B'Elanna Torres, despite her misgivings, decided to go through with this ceremony, she entered a holodeck simulation in which simulated Klingon warrior named Moklor told her that she was endure this ritual in order to test her mettle. This was to be followed by her engaging in combat with a master of the bat'leth and traversing the sulfur lagoons of Gorath.
Upon hearing this, Torres replied that she had not wanted to go through with the ceremony before hearing all of that and wanted to even less now. She then made to leave, only for Moklor and other Klingons in the simulation to begin jabbing her with the painstiks, at which point she attacked Moklor.
Encountering her later, Tom Paris stated that he had visited the simulation looking for her, only to find a Klingon who looked like he'd had a run-in with someone who had a very bad day. (VOY: "Day of Honor")