Surprisingly, it's Sharon!

You continue to fuck Christine hard, all the while taunting her for being such a slut.

"You love my cock, don't you," you ask.
"Yes," the MILF exclaims.
"Tell me to fuck you harder! Tell me to fill you up!"
"Please fuck me harder, Master! Fill me up!!!"

Tory, meanwhile, is alternating between licking Sharon's pussy and spanking her. Either one is getting a strong reaction out of her, so the combination of the two is really doing it.

"Tell me to spank you harder," Tory says, showing her dominant side.
"Spank me harder, Mistress," the redheaded MILF cries, "I love it!"

Making her **** happy, the busty co-ed does just that. You can't see it, but Sharon's ass has turned a really bright red by now. You can only imagine how hard it will be for her to sit for the next hour or so!

At this point, it's a race to decide just who will cum first. Will Christine succumb to your dick or will Sharon betray her attitude and cum like a little bitch?

"Oh shit, I'm about to cum," Sharon shouts, "Permission to cum, Mistress!"
"Hmm, what do you think," Tory asks, looking over at you.
"I think so. 'Mom,' tell your friend to cum like the whore she is."
"Cum, you whore," Christine shouts, "Cum for us!"
"I'm fucking cum-ming," Sharon exclaims, "I'm fucking cum-ming!"

The buff redhead struggles against her bondage, but can't get loose. In spite of that, she cums hard and writhes like a woman possessed! With all of her talk of being strong-willed, you're surprised to see her act like this.

"Thank you, Mistress," Sharon says, not needing to be told to.
"You're welcome, ****," Tory says, leaning her naked body over the woman and kissing her on the cheek, "You owe me though."
"Yes, Mistress."

The show isn't over yet, as Christine is about to cum herself. Did Sharon's display aid her?

"Permission to cum, Master," she cries out.
"Say 'Mommy needs to cum' and you will be allowed to," you reply.
"M-mommy needs to cum! Mommy needs to fucking c-u-um!"

She cries out what you order and then gets the release she needed. Like Sharon, her body struggles for freedom, but finds none. Instead, it writhes as much as the tight ropes will allow.

"Th-th-thank you, Master," she says, once the rush of energy has passed.
"You're welcome," you reply, "I just hope that your daughter fucks as well."
"But...but you promised..."
"I lied," you say, slapping her on the ass, "Now which one of you two wants to be fucked more."

Both Sharon and Tory look over at you- the latter still laying across the former's back- and plead their case.