I used to sing that one years ago as as a youth! The more accurate operatic version goes:

Last night I tried my hand at masturbation,
It did me good; I knew it would.
Tonight I will repeat the operation,
It will be nice; I'll do it twice.
First I gave it a short stroke,
Up and down, up and down,
Then I gave it a long stroke,
And tickled the ground, and tickled the ground.
Squeezed it, pleased it, rolled it in floor,
Smashed it, bashed it, slammed it in the door.
Some people tell me that the art of sexual intercourse is grand,
But I know that I prefer to hold it in my hand.