This is the full version of the German Bedtime Story from Family Guy.

The Story of Little Suck-a-Thumb
One day, Mamma said, "Conrad dear,
I must go out and leave you here.
But mind now, Conrad, what I say,
Don't suck your thumb while I'm away.
The great tall tailor always comes
To little boys that suck their thumbs.
And ere they dream what he's about
He takes his great sharp scissors
And cuts their thumbs clean off, - and then
You know, they never grow again."

Mamma had scarcely turn'd her back,
The thumb was in, alack! alack!

The door flew open, in he ran,
The great, long, red-legged scissorman.
Oh! children, see! the tailor's come
And caught our little Suck-a-Thumb. 

Snip! Snap! Snip! the scissors go;
And Conrad cries out - Oh! Oh! Oh!
Snip! Snap! Snip! They go so fast;
That both his thumbs are off at last.
Mamma comes home; there Conrad stands,
And looks quite sad, and shows his hands;-
"Ah!" said Mamma "I knew he'd come
To naughty little Suck-a-Thumb."