Here's the way Hot Tuna sang it:

Well now keep on truckin' mama, truckin' my blues away
Keep on truckin' mama, truckin' my blues away
Here you come mama big as sin, tell what you been doin' by the shape you're in
So keep on truckin' mama, truckin' my blues away

If you been doin' what I think you been doin' baby, can't do that 'round here
You been doin' what I think you been doin' baby, can't do that 'round here
Here you come mam big as hell, tell what you been doin' by way you smell
So keep on truckin' mama, truckin' my blues away

What's that smell like fish pretty baby, I really would like to know
Tell me What's that smell like fish oh mama, I really would like to know
That ain't puddin' baby ain't no pie, it's the stuff that I got you by
So keep on truckin' mama, truckin' my blues away

Now yes you gotta leave this mornin', get your yas yas outta my door
Now yes you gotta leave this mornin', get your yas yas outta my door
Ashes to ashes mama, dust to dust, what-cha gonna do when that damn thing rusts
So keep on truckin' mama, truckin' my blues away

It appears Hot Tuna got their name from an answer to the question,
"What's that smell like fish oh mama" in the 3rd stanza of this song.