"Heat of the Moment" is a song originally by the band Asia. Eric Cartman sings the song to convince Congress, who eventually join in, to fund stem cell research in the Season Five episode, "Kenny Dies".
I never meant to be so bad to you
One thing I said that I would never do
A look from you and I would fall from grace
And that would wipe the smile right from my face
Do you remember when we used to dance?
And incidents arose from circumstance
One thing led to another we were young
And we would scream together songs unsung
It was the heat of the moment
Telling me what my heart meant
The heat of the moment showed in your eyes