Was it a bunt, or a swing with 2 strikes

[Del-Blue]

As the PU how do you decide if the batter tried to bunt the ball or was it actually a swing.
I had this yesterday, and the U of D coach thought the batter tried to bunt, I said it was a swing. She asked if I could confir with my partner, which I did. We decided it was a swing,ok, we play on. At the end of the inning, she asked me if I could explain why it wasn't a bunt, and how I came to that decision. I told her that the determining factor was that she passed the bat through the strike zone, with a breaking of the wrists. Sort of like a short check swing. An attempted bunt would be just presenting the bat at the ball with a push. I never really thought about attaching a definition to a bunt, I always knew it when I say it.
The NCAA defination is: A legally batted ball not swung at but intentionally tapped with the bat.