This song varies per person really..add whatever you see fit,it's a fun Irish song. Start off slow and gradually get faster..by the end you should be singing it so quickly that nobody will be able to follow you......

Oh ro the rattlin bog, the bog down in the valley oh
Oh ro the rattlin bog, the bog down in the valley oh
And in that bog there was a hole, a rare hole, a rattlin hole,
There was a hole in the bog, the bog down in the valley oh,
Oh ro the rattlin bog, the bog down in the valley oh
Oh ro the rattlin bog, the bog down in the valley oh
And in that hole there was a tree, a rare tree, a rattlin tree,
There was a tree in the hole, a hole in the bog, the bog down in the valley oh,
Oh ro the rattlin bog, the bog down in the valley oh
Oh ro the rattlin bog, the bog down in the valley oh
And on that tree there was a branch, a rare branch, a rattlin branch,
A branch on the tree, a tree in the hole, a hole in the bog,
In the bog down in the valley oh,
Oh ro the rattlin bog, the bog down in the valley oh
Oh ro the rattlin bog, the bog down in the valley oh

There is no last line...whenever you are about to explode should be a good indication!

My last line is usually...
A wing on the flee, a flee on the feather, a feather on the wing, the wing on a bird, the bird in an egg, an egg in the nest, th nest on a leaf, the leaf on a twig, the twig on a branch, a branch on the tree, the tree in the hole, the hole in the bog...in the bog downnnnn in the valleyyyyyyyyy OOOOOOOOOOOOOOOOOOO   

(Read it from the end back and you will get the meaning!It's best to picture the things going on as you sing it.)