Stop this and take your reward.

You sneak out from your hiding space and pull out your phone. You quickly take a bunch of pictures of Brad as he stands with his dick out in front of his naked Sister.

He hears the sounds and sees the flash, stopping in mid-thrust attempt. His cock is inches away from Lilly's pussy.

"What the hell, man?!?"
"I could ask you the same question," you say, "About to **** your sister?"
"It is none of your business," Brad says, "Get out of here."
"Sure. Let me just send these pictures out to everyone."
"You wouldn't!"
"He would," Lilly says, recovering her confidence, "Now get out. I'll decide how to punish you for this later!"

Brad has no response, so he grabs his clothes and leaves in a huff.

"And lock the door behind you," she adds.

You two hear the door lock and Lilly gets up next to you, hugging you tightly.

"Thank you so much, Alex. I'm sure that you were scared of him. A lesser man would have just stayed hidden."
"I couldn't do that," you reply, "No real man could."
"Speaking of a real man..."

She reaches down to your pants and undoes the zipper. She pulls your cock out, finding it to be pretty hard.

"Instead of letting that guy take me against my will...how about I let you do it?"

She winks and you nod. She pulls your belt out of the loops and hands it to you.

"Tie me up and take me, Alex" she says, "I totally don't want to fuck you."