First of all, kudos on coming up with an interesting angle.
Now, to address this insanity.
I don't have glass patio doors.
No, no, I'm just kidding! I do! Wouldn't that have sucked? I could've just bailed right there, and the person who asked this question would be totally boned! He'd have no way of arguing that I do, in fact, have glass patio doors! Ha!
Okay, now for the truth. When I get a question through my site, it tells me the time it was sent. I wasn't at my computer when this was sent. I'll give you the benefit of the doubt, that though you claim in your question to be watching me at that very minute (liar), you could've asked the question slightly before or slightly after. But I'm guessing it was around that time, if you had the balls to claim it was happening at that very moment. I was cooking, and I was back and forth between the kitchen and the living room. Because one of those journeys forces me to face the sliding doors, I would've seen you. Even had it been at night, pretty hard to hide behind glass, therefore hard to do as you've claimed without notice. Maybe if you caught me masturbating I might not notice you...
Short Answer: I guess try that next time. I'm usually masturbating anywhere between all the time and whenever.