Volbeat used Helping Hand!

Helping Hand is an increased priority move that will raise the base power of the adjacent ally's move in a Double Battle and Triple Battle by 50%. It will fail if used in a Single Battle. It will also fail if all of that Pokémon's allies have already moved.

In the anime, Helping Hand was shown to be a cheering move that strengthened the attacks of the user's allies, as demonstrated here. That's where the idea of the pom-poms came from: Volbeat is doing a cheer routine. The pom-poms' colors are based on snowcones Volbeat's color scheme.

This is a drawing for Pokemon Fan Forever's Pokemon Moves Contest. The deadline for the contest is October November 29th, so feel free to join in if you're reading this an happen to be interested.