There is, but Sharon doesn't like it.

"Yes, there is another way," you say, "If you two won't put on a show for me, we'll go with Plan B."
"What's Plan B," Sharon asks, looking at you curiously.
"It's simple- I fuck you!"

"Get down on your knees and lick me," Christine says to her friend, "It's the best way."

Reluctantly, the woman lowers to her knees and moves her head towards her friend's crotch. You grab her by the hair and stop her.

"No no, it's too late for that," you taunt, "All you did now was agree to suck my dick. We'll still decide which one of you I fuck first later."

The woman sighs in **** acceptance as you unzip your fly and pull out your dick. You wave it in front of her face in a taunting manner.

"Remember, anything I do to you is something that I am not doing to Donna."

The woman moves her head forward, reaching for your cock. She begins to suck it- without the aid of her hands. You did bind her elbows and wrists, not to mention the tie connecting her wrists to her crotch-rope.

You draw this out for a bit, wanting to really break the strong woman's spirit. You get an idea.

"Tell her to suck me better," you say, slapping Christine on her right tit.
"What?!?"
"Tell her to suck me better," you say again, slapping her left tit this time.
"S...suck him better," Christine mutters.
"Do it better!"
"Suck him better."

"Good girl," you say, rubbing her tits with your free hand, "Tell her to be a good cock-sucker."
"Be a good cock-sucker."
"Tell her that she's a cock-sucking whore."
"You're a cock-sucking whore," Christine says, looking away.

Just for added fun, you take your other hand back and **** Sharon to deep-throat you. She gags a bit, but manages to hold you in. You may get more use out of her yet!

You finally let go of her after a minute and pull your dick out, slapping it lightly against her cheeks.

"Good job. Now I'm all lubed up. The question is..."