I say it was a random thought not even realized. You say you were drunk right? She was probably getting into having sex with you, really really relaxed and Kenny just popped out. Like when you are meditating and things just come to your mind, strange things with no real tie to what is at hand.
I say just let it go. She is probably beating herself up for her mistake already. I doubt it will happen again. And if it does, then there is your problem.