Watching the Neighbor Girl

I hope this is not against the rules of this site, but it has been going on for a while, so I wanted to write about it.

I enjoy masturbating outdoors - I want to write about it eventually, but this happened (or happens?) in my apartment.

I live in an apartment on the 5th floor, and there is a building right across from me. That building is smaller, its top floor is one level lower than mine, so I can see into the balcony/bedroom of a flat. Not that there is much to see - a pretty girl in her 30s lives there, but she closes the curtains and stuff, I could only see her once naked inside. But she is a smoker, so she sits out on her balcony quite a lot, sometimes alone, sometimes with a girlfriend. On a nice day, she sits there with an occasional drink, enjoying the sun, or fixing her flowers/plants, playing with her phone, talking, people-watching, and so on.

Me, being my horny self, sometimes watch her when I need to cum - it is so much fun touching myself while she is about on herbalcony. I can cum pretty fast.

This has been going on for a while now, I pull up a chair to my window, pull out my phone and some cream, and go to town (the phone is needed so I can see her up closer - and I also record the whole thing, sometimes reliving it all later, having more fun of it all).

One day she had a close friend over, another girl about her age - thin, black hair, also cute. They were sitting outside, chatting, drinking and smoking, I decided to have a nice wank while looking at them.

As I was watching them, and stroking my lubed up cock, the girl living there stood up, going back inside. I was worried they were leaving without my cumming, so I started to beat it faster. This girl went inside, the other stayed, and I started to cum - but actually, I was so loud that she heard me! She started looking around when she heard the first grunt of about three, and saw me (or my hand, holding my phone since she couldn't look into my place) - and smiled! I am sure she knew what happened.

It is such a thrill to know that she KNEW I have cum watching her...well, since I recorded it all, I still have the video on my phone and I relive it often, especially on cold winter nights (or days).

I know I am a pervert for doing this, but is this illegal? I am not harming her/them in any way, but I enjoy it a lot...

One day soon after that (the following week) I ran across the girl who lives there walking down the street, and she gave me a strong look. Maybe her friend told her what she heard...I wonder. I wish I could cum for her friend again, but I have been trying to be quieter when I cum, I don't want to get into trouble. I am looking forward to the summer :)