...Are they singing Pettan Pettan Tsurupettan?

cybeast said:

...Are they singing Pettan Pettan Tsurupettan?

Nopes, the singing bit is just 'pettanko' repeated. つらぺったん is 'tsurapettan' and ぺったん子, which also says pettanko, is flat chested girl.

I thought Ikazuchi was about to have a fingers problem for a second there, but I guess Inazuma has better aim.

Voice bubble said:
Chopping board

Oi... That's cutting it a little close there, ain't it?