This is how I remember the words as sung by Patrick Sky on his album:

RATTLESNAKE MOUNTAIN

On rattlesnake me-y-mountain I did dee-y-dwell
And I've got a stee-y-story I'm a-gonna tee-y-tell.
Come a roodi roodi roo.
A nice young mee-y-man in the month of mee-y-May
Went down to the fee-y-fields for to mow his hee-y-hay.
Come a roodi roodi roo.

He had not mow-y-owed all around that fee-y-field
When a rattle copper snee-y-snake come and bit him on the hee-y-heel.
Come a roodi roodi roo.
He jumped up a hee-y-high and he looked all a ree-y-round
And he closed his ee-y-eyes and he fell to the ghee-y-ground.
Come a roodi roodi roo.

He told the bee-y-bird, "Go fetch my ghee-y-gal.
I'm rattlesnake bee-y-bit and I need my see-y-Sal."
Come a roodi roodi roo.
The bird did flee-y-fly and spread the new-y-ews
And along come a see-y-Sal without any shoe-y-oos.
Come a roodi roodi roo.

"Oh, Johnny dee-y-dear, why did you go-y-wo
Down into the fee-y-fields a hay for to mow-y-oh?"
Come a roodi roodi roo.
"Why, Sally d-y-dear, I thought you'd know-y-oh.
When the hay is ree-wi-ripe it's a-gotta be mow-y-owed."
Come a roodi roodi roo.

"Oh, Johnny dee-y-dear, I'll save your lee-y-life
If I may be-y-e your sweet little wee-y-wife."
Come a roodi roodi roo.
She grabbed his lee-y-leg and made him squee-y-squeal
And sucked that pizon blood right out of his hee-y-heel.
Come a roodi roodi roo.

Now Sal she hee-y-had a rotten tee-y-tooth
And the pizon stee-y-struck and killed them bee-y-both.
Come a roodi roodi roo.
The nee-y-neighbors found that they were dee-y-dead
And laid them bee-y-both upon one bee-y-bed.
Come a roodi roodi roo.

So all young lee-y-lovers a warnin' tee-y-take
From Johnny Bee-y-Bland and Sally Bee-y-Blake.
Come a roodi roodi roo.
And mind if you're in lee-y-love, don't pee-y-pass
Too close to pee-y-patches of high ghee-y-grass.
Come a roodi roodi roo.