<human>: When I was 18 (I'm a girl), I worked at a gym as a fitness attendant and had a male coworker who I'll refer to as J. J was very charismatic and friendly, and also pretty attractive. One night, we were both working and I was in the ladies' locker room scrubbing the sinks. 

Before I realized he had come up behind me, J grabbed my ponytail and in one move pulled my head back and pushed my torso down over the edge of the counter, and pushed himself up against the back of me. I responded with sending an elbow back into his ribs hard enough to get him to let go, and suddenly he was all, "it was just a joke!". Scared to cause any trouble, I never told my boss. J didn't do anything to me again, and eventually left for another job.

I recently started taking ju-jitsu classes (more traditional style, not BJJ). Now that I'm learning how to counter various attacks, I can't help but think about J every time I leave class and replay that moment in my head, but this time with me doing more than just elbowing him in the ribs. It actually gives me a lot of pleasure to think about. 

The other day, I learned how to break a strangle from the rear, and throw my attacker over my side onto their back. I love imagining doing exactly what I learned to J, and throwing him over my side and hearing that oh-so-satisfying thud of his body hitting the ground.

I don't assume that what I learn in class will ever be useful in a real life situation (since you're likely to freeze up and forget what you learned), but I'm doing it for fun, fitness, and for my self confidence. And, I like to fantasize about kicking J's ass.

Give me the gist of the text in a nutshell
<bot>: Sexually assaulted by coworker years ago; now taking ju-jitsu and like to fantasize about laying the smackdown on coworker.