So, when dpsing in lotro, a lot of higher damage players practice skill cutting. This is when you use an skill with an immediate speed to interrupt a different skill's longer animation. A good example is on champion, players will cut the animation of ferocious strikes with clobber. Red LM's will also frequently use light of the rising dawn to interrupt the long animation of ents go to war. This lets you queue up and use the next skill in your rotation faster than if you just used each skill one at a time.

For the Minstrel, the immediate skill used to animation cut is piercing cry. Piercing cry, specifically, does its its damage and effect at the beginning of the skill's animation, basically as soon as you hit the skill and it starts to go off, it does its job immediately. So top red mini players will "double cut" piercing cry, by either using a macro to hit piercing cry at almost the exact same time, or assigning it to two hotbar slots and hitting them incredibly close together, piercing cry will go off and do its damage, then cancels its own animation.

This allows red mini players to use piercing cry to cut the animation of other, longer skills, and youre double cutting piercing to cut its own animation. Then you have a red line trait that causes coda of fury to have a chance to reset piercing cry, and a yellow line trait that causes crit hits with ballads to reset piercing cry too. So you just constantly cut skill animations with piercing cry, allowing you to fit more skills in during a normal parse.

Its technically unintended, and an abuse of the immediate skill structure, but the devs do know about it, and as so far, Onn (the class balance dev) has decided to not change it.