Fa la la la - A sound you make when you're trying to be festive but your b

A sound you make when you're trying to be festive but your brain is on fire from too much sugar and too little sleep

I stayed up too late eating cookies and my brain exploded into 'fa la la la' when I tried to sing.

My sister was so hyper from the candy she kept screaming 'fa la la la' at the top of her lungs.

I was so tired from wrapping presents I just blurted out 'fa la la la' and couldn't stop.