Mrs. Pendragon volunteers.

Tiffany and Candace look at each other nervously. It is tough because they have no good option here and must decide between what is worse.

Mrs. Pendragon tries to communicate through her ball-gag, which gets your attention. You push her head down and undo the strap. You pull it off of her, holding it near her in case you change your mind.

"I'll do it," she says, "I'll make you happy, Master."
"Really," you say, "You'll suck my cock?"
"Yes, Master."
"You'll take my spankings?"
"..yes, Master."
"You'll let me fuck your face while I pull on your nipple clamps?"
"...y...yes, Master."

"Very well. It's time to earn that extra credit."

You reach out and grab both nipples in one go. You walk backwards, compelling her to go with you. You sit up on your desk and whip out your cock. She gets in position in front of you, down on her knees like your bitch.

"I'm waiting, slaves," you say, slapping your dick against the Teacher's face disrespectfully, "Get to it."

The naked pair look into each other's eyes and share a secret conversation. They bridge the small distance between them and begin to make out. While they still have their hands bound behind their backs, they still do this pretty passionately.

"Ahem," you say, slapping your member against the Teacher's face.

She looks up at you with sad acceptance and moves her head to grab your cock. With her hands also bound behind her back, she has a tricky job ahead of her. She manages to get your cock in her mouth and begins to suck it.

Back in front of you, the pair have split off from their kiss.
You see that Tiffany is kissing down Candace's neck, who appears to be whispering to her. You don't care what they're saying- you just want to watch the show.

She moves down to Candace's DD rack and kisses them all over.
It isn't long before she moves to the nipples, eliciting some lovely moans from one of your slaves.
She alternates between them both, which you're sure would be easier if she wasn't tied up right now.

Mrs. Pendragon continues to suck your cock, showing surprising interest in it. You half-expected her to try and sneak by with little effort.
Instead, she's sucking your cock excitedly and seems to be enjoying it. You'll press her on this later.

The bound pair in front of you, it seems, have switched things up. Candace is now kissing Tiffany's neck, eliciting some moans from her this time. She moves down and gives her girlfriend a similar treatment. Tiffany's breast are C-Cups at best, but still lovely to look at.

After a few minutes of this, she stops and looks over at you. She sees her former-Teacher sucking your cock like a filthy whore.

"Let me make this very clear," you say, "Either you two start licking each other's pussies or I'm going to fuck them. Decide quickly."