A Brutal Slasher Story - Please Add On To This

You can't hold back at the sight infront of you, and the fact that you in danger of being caught as a peeping tom, really intensifies your arousal.
You reach down into your pants and start to fondle your penis. You know you can't hold back and you unbutton your pants and drop the zipper, letting your pants fall to the ground.

You penis is still a bit soft so you rub it against your leg a bit, not yet in full masturbation, as you watch Samantha. She is obviously shampooing right now, and she lathers up her tits with a bit of extra shampoo while turning to face you. She is completely exposed to you but the combination of the night glare and the fact that she has her eyes closed as to not get soap in them, keeps her from spotting you.

You now are unable to control yourself and start masturbating with vigor.
Now what?