1. Duel the player.
2. Write /pvp.
3. Start Fighting.
4. Write /forfeit or /yield.
5. The chances are big that he will hit you atleast 1 time after you yielded since your PvP is on.
6. If he hits you he will be PvP flagged.
7. Kill Kill Kill.
I hope this is not a repost and iam just trying to contribute.