Fightsong

You can sing glorious songs of goblin victories to rouse your allies.  You and all allies who can hear you have advantage on the first attack roll each round while the song endures.  In addition, if anyone under the song's effect rolls a 1 or 2 on a damage die, you may reroll the die and must use the new result.

Beginning the song takes an action and you must use a bonus action each round thereafter to maintain it.  If you choose to not maintain the song, it ends at the beginning of your next turn.