Punish her.

"Stay there." you ordered as you left the room, then returned with a ball gag and a device with a red cone, black handle, and two metal prongs at the tip of the cone. It had some buttons on the side. It was called TaZapper, used for electro stimulation. You hadn't known what would make her regret being a tormentor, so you grabbed whatever you thought would help.

"Is that really necessary?"

"You lied about why Sarah stayed with me, especially texting the photo I wanted to text to her." you said, stalking over to her. She wasn't intimidated, but you didn't care, she was going to be after a week of this. You grabbed her blanket and pulled it off, revealing that she was still naked. You sat the gag down, reached into your pocket and grabbed one of two pairs of cuffs and put them on her wrists, but didn't connect them. You did it with the second pair, but those went on her ankles. You connected right wrist to right ankle, same for the left wrist and ankle.

She was exposed and naked. "You don't need the gag." she said "You want me to say sorry for not telling you that I had Sarah help me keep tabs on you and send her the photo you wanted to send? Then don't put it in."

You thought for a moment, then just put it around her neck "It goes in if you don't say it."