Lyric provided by www.seekalyric.com

Quagmire [talking]: Ensign Glen Quagmire. Welcome aboard.
You picked a great day to get rescued.
We were just about to sing a song about mopping.

Quagmire's sea crew [singing in opera type tune]:
We're mopping the deck
which is Navy for "floor"
And when we're done mopping
We'll mop it some more.

Quagmire [in his custom voice] Oh!

[Singing again]: Swab means mop, deck means floor.

[End, interrupted by death's mum]