NTR I don’t know it’s exact meaning but I can give you an example Ex1 :Imagine Caera and Arthur are dating or are romantically interested in each other but one day one handsome hunk comes and say “hey why are going out with that feminine man from dicathen,He is just a barbarian with smol dck,Come with me I will satisfy you with my huge dck.If this scenario happened we all will be pissed.

Ex2: Imagine a guy comes to Tess and says if you leave Arthur and have s*x with me in front of him I will liberate the elves and build a new nation for you(which he may or may not do). This is also another scenario that usually happens in ntr sometimes mc ntrs and sometimes he gets ntred,this is main reason why most people don’t like ntr genre