Here's the lyrics:

Mr. Custer
Larry Verne
Words and Music by Fred Darian, Al DeLory, and Joe Van Winkle

Peak Billboard position # 1 in 1960

(That famous day in history the men of the 7th Cavalry went riding on)
(And from the rear a voice was heard)
(A brave young man with a trembling word rang loud and clear)
What am I doin' here??

Please Mr. Custer, I don't wanna go
Hey, Mr. Custer, please don't make me go
I had a dream last night about the comin' fight
Somebody yelled "attack!"
And there I stood with a arrow in my back.

Please Mr. Custer, I don't wanna go (forward Ho!!)--aaww

SPOKEN: Look at them bushes out there
They're moving and there's a injun behind every one
Hey, Mr. Custer-you mind if I be excused the rest of the afternoon?
HEY CHARLIE, DUCK YER HEAD!!
Hmm, you're a little bit late on that one, Charlie
Hooh, I bet that smarts!

(They were sure of victory, the men of the 7th Cavalry, as they rode on)
(But then from the rear a voice was heard)
(That same brave voice with the trembling word rang loud and clear)
What am I doin' here??

Please Mr. Custer, I don't wanna go
Listen, Mr. Custer, please don't make me go
There's a redskin a-waitin' out there, just fixin to take my hair
A coward I've been called cuz I don't wanna wind up dead or bald

Please Mr. Custer, I don't wanna go (forward HO)--aaww

SPOKEN: I wonder what the injun word for friend is
Let's see--friend-- kemo sabe, that's it
KEMO SABE!, HEY OUT THERE, KEMO SABE!
Nope, that itn't it
Look at them durned injuns
Theyre runnin' around like a bunch of wild Indians-heh, heh, heh
Nah, this ain't no time for jokin'

I haven't found the tune on the web yet, but lots of people did it. Is Napster still up and running? If so, you might put Mr. Custer in and see what comes up.