Weird Story

So I am an office assistant at a small commercial construction company. I really like my job and most of the people I work with. I do have some interesting encounters with people, but none like the one I had today.
We are getting a new security company and today they stopped by to finish up some paper work so they can install it on Monday. It was a husband wife team that came by. They seemed friendly and were up in the waiting area with me while they were waiting on my boss. I am pretty bad about entertaining people. I usually have them sit while I continue on with my work. Well today this did not happen....
I was filing some paperwork and the man comes up to me, inches from my body, (definitely an invasion of personal space) while I am standing (luckily) at the filing cabinet and he says to me, "I have a weird question.....then he proceeds to put his hand in front of his crotch wave it around like he is peeing and makes a "PPIIISSSSSSSSSSSS" sound. He is practically touching me and I am speechless. Am I really watching this? He says nothing else and I make some sort of sound and point down the hall. I felt so violated, it was the weirdest thing. He never asked for the restroom. My friend was standing up there watching this whole thing and asked me did he just do what it looked like. I nodded silently and she left me to go laugh outside. It has been a big joke all day here in the office. Seriously who does stuff like that?