It felt amazing. She just did it out of nowhere. Wonder how she knew to try it...
Replies 9

Ask her that. It's a fair question.
But there's an issue you might need to consider. One of the classic signs of cheating is that the other person suddenly starts liking different things in sex. If you see any more signs like this, you may have a problem.

oh shit, stop asking questions and enjoy it, if nothing else encourage her, show her that you appreciate her effort to make you enjoy yourself
awesome. She has always loved ass play on her, but never tried it on me.
Woul love to hear more of you folks stories about it.