"
sing.
Worms come out of the woodwork.
Leeches crawl from out of the dirt.
Rats come out of the holes they call home.
I fall apart,
And the snakes start to
He is trying to explain how all the ugly, disgusting things hide in places we don´t even stop by to check, as in our own personal demons. And when he says "I fall apart, and the snakes start to sing" he means that he can´t hold himself in anymore and that everything comes out to light.