GOAT Cuck Bro?

I'll keep it short and simple. I am a 25 year old male and I have a sis who is 2 years elder to me. She is very promiscuous and careless. Careless because she is now bringing guys home thinking no one is home and not even double checking. So cutting to the chase, I've been watching her have sex for almost 10 months with like 20-25 diff guys for almost twice a week if not thrice. AND I LOVE IT.
It is so hot and sexy. I know she doesn't know as I watch from a window vent which is on the wall right beside a staircase.
But now I want to see more. Things like double penetration, someone hardcore fucking her, her showing me the cum in her mouth before she swallows and more.
And the most fucked up thing I wanna do is "HELP"
Help as in I want to see her in cowgirl position and when the dick slips out, I want to be the one to put it inside her again. MANNNN