I used to work part time in a supermarket when I was at uni. One of the delivery guys was a complete sleeze. He used to try it on with all of us. We were all late teens/early 20s and he was around 40 at the time. He took a shine to me and just wouldn't get the message that I wasn't interested. Had a male colleague of mine pestered to persuade me to go out with him.
One day at work I came around a corner and saw him talking to that colleague. Colleague was facing me and sleezy guy had his back to me so he didn't see me. Arrived just in time to hear him tell my colleague "I'm not looking for anything serious with Cassie. I just want a quick duck"
I tapped him on the shoulder, he turned around and I said "duck off John! Now, was that quick enough for you?"
He never came near me ever again.