Hi!
As the title says you can easily flag enemy players just by using Explosive Decoy - Item - World of Warcraft
For this you need at least 350 Engineering skill
By placing this decoy you will spawn a small rabbit. This little guy will not get attacked by city guards, but can be slain by any player. However by attacking him you will get instantly pvp flagged (combat pet!!!)
Just go to random enemy faction city, place the decoy and wait for fun :wave: