Dressed in an outfit adorned with the talk show's face (naturally), the singer explained how she often goes about writing her tunes.
"What I do is, I turn off all the lights, and I walk over to the piano and I gently lower myself, my boobs, and they go on the keys and I just let them tickle the ivories. They really just go crazy," Ke$ha revealed.
As if that wasn't enough, the songstress proceeded to give O'Brien not one, but two gifts. First, a pair of briefs with her face on them, and then, a fan's tooth dipped in gold. (Yes, you read that right.)
"I'm wearing your underwear, I've got the tooth, and thinking about your breasts playing the piano. This is the greatest night of my life," O'Brien quipped.
And one that we certainly won't forget any time soon, either.