This ability is used similar to a warrior's Sunder Armor, though it does not generate as much threat. However, Lacerate can crit, which increases the threat caused.
The damage over time is divided into 5 3-second ticks (one-fifth of the damage each tick). Reapplying Lacerate renews the DoT debuff to its full 15-second duration.
Tips and tactics
Very good skill for single target tanking. The tanking rotation generating the most threat is: Mangle as often as possible; while Mangle is on cooldown, use Lacerate; if you still have excess rage, use Maul in parallel.
When tanking multiple mobs at once, Swipe (Bear) is usually a better choice than Lacerate.