Getting romantic with oneself outside of someone else's window.

Some nights are just long. Some nights are just hard. Some nights I wish I didn't see naked men scampering around my apartment while feeling something long and hard.
So the other night I am sitting on my couch in my underpants watching Mad Men like most nights. I hear what sounds like noises you'd hear in the heat of passion, they were loud and sounded like they were right outside my patio. I texted my boyfriend to tell him about the loud sex my neighbors must have been having on their balcony. I will not include what was also said in the discussion, but you get my drift. The next night, same position (on my part) around the same time, Mad Men and a slushie were making my night enjoyable while 'my neighbors' partook in their nightly enjoyment. It was so strange how close it sounded and I just couldn't understand why it sounded like it was on my patio, so I flip the light on and look out the glass door to investigate. Nothing. The next night, same thing. I was becoming a little annoyed with the timeliness and consistency of these moans of pleasure. I wondered if that routine of theirs was getting boring. Saturday night I actually went out so I didn't find out if they were going for a 4th night in a row. Sunday night, same time same place. I even went to the extent of going out my front door to see if I could hear it from anywhere else, they were really loud. Though it was always the same noise and tone. Now we come to Monday night. I switched to Mad Men and a particularly sad episode at that. No sounds. I was overjoyed to not have to awkwardly listen to moaning while I'm watching Betty tell Don she doesn't love him anymore. Phew.
Then my boyfriend makes the usual bedtime phone call. We chat for over an hour and I mention that my neighbors are starting later than usual and they must have taken it to their bedroom this time because I could hear it while laying in bed. I had gotten into a habit of sleeping with a lamp on after the break-in and this night was no different. As I was saying 'goodnight' I saw a movement in my window. The blinds were closed but I was certain I saw something, enough to get my heart racing. So I do what girls do when they get murdered and I investigated outside without a weapon or mace.
This is when things get sticky, thankfully not literally. As I am standing outside of my front door I am looking here:

Imagine it being dark and the only light is coming from behind me. In that space between the buildings I see a man, completely naked, cock in hand run from left to right. I sat for a second rubbing my eyes to make sure I had just seen that correctly. I knew I had when I saw two heads pop around the right side corner of the building. I walked towards the rocks and yelled 'What the **** are you doing?' The only movement I saw was a continuous masturbatory motion in which the only part of the body I saw was hand and penis. Even after yelling the motion continued and I bee-lined for my apartment and called the police. They showed up within 15 minutes, looked around with flashlights and stuck around the parking lot for quite a while. I filed a report. I texted my sister and her and her boyfriend were insistent on coming to get me and not letting me stay there.
This is not the first time in my life I have been confronted with a masturbator. Detroit. That's for another time though.
Ladies and Gentleman, follow your instincts and keep your clothes on in public.
Thank you and have a lovely evening.