The Singing (Shouting) Bee

Brennan and Nicholas have hit that male competitive steak. Full stride. Lately it has manifested itself as a singing bee of sorts. Here's how it generally goes:

-One boy starts singing a song.
-The next boy says "No, lets sing this song."
-First boy says "No, I want to sing my song."
-Both plead for me to intervene. I offer "You cannot make other people sing what you want them to.".
-Both boys then proceed to each sing his own song simultaneously. One gets louder, then the other gets even louder, and bingo! Competition ensues.
-Mom gets immediate migraine. Tells both boys to just stop.
-Boys both look at each other and grin broadly. Game over! Winner - boys. Loser - Mom!