Strip and see

"First, I want you to strip her. When she is all nude, you will tie her up."

"In what position shall I tie her, master?"

"You will decide how and in what position. I will give you a hand if she has to be lifted."

"But why do I choose, I thought..."

"This is your reward, Donna. You will tie her up, wake her up, and then I will fuck her in all ways you want me to, and you can watch or join. Big bad sis is now the bad **** of a good ****."

Donna, thought some moments, then she acted very determined, even putting on a wicked grin.

"You will love it, master."