Four times.

Donna enjoys being in charge right now and takes all of her frustrations out on Dee.

What did she do when Donna was kidnapped? Why didn't she rescue her? How did she end up a Sex **** too?

That bitch must have asked to be a Sex ****- it's the only thing that makes sense to Donna.

After a minute, Dee looks at you sadly.

"May I please cum, Master?"
"You may, slut."

She cries out into her rope gag, making Donna smile. There's something else though.

You hand her a large vibrating wand and she knows what to do. She just does what you would do to her in this situation.

It's only another minute before...

"May I please cum again, Master?"
"You may...but next time, ask your Mistress."

She looks at Donna sadly as she cums again. She let her down! She's such a dirty slut for liking this deep down!

"May I please cum again...Mistress," she asks roughly 2 minutes later.
"You can on 3. 1...2...2.5...3!"

She cums even harder after being teased. Why does that turn her on?!?

Another orgasm comes a minute later and you order Donna to stop. Just to make things clear...

You order your man to come over and undress Donna.
You have him tie her up a bit while she is once again naked and you make her beg to have nipple clamps put on her.

As she puts the chain in her mouth, you make her tell you who she belongs to.

"I belong to you, Master," she manages to say, barely keeping the chain still.
"Good. Don't you forget it. Now it is time to punish your Step-Sister again some more. Enjoy the show."