Anna slowly creped along the hallway, hugging the wall. She peaked ahead to the bathroom. She could she that the door was slightly ajar. She could hear Elsa breathing heavily from inside the bathroom. Anna grinned to herself. She knew what Elsa was doing in there. Sure enough, as Anna popped her head through the crack in the door, she could she Elsa, completely naked, with her legs spread, going at it with a partially melted icicle. Anna's heart skipped a beat. She had caught her sister masturbating. She had been trying to catch Elsa for the past month, but Elsa was just too careful. This didn't discourage Anna. She kept following Elsa, knowing that one day she would slip up and leave herself exposed. And that day was today.

Anna watched her sister carefully, making sure not to make a sound. She hid herself in the shadow cast by the door so that Elsa couldn't see her. From there, Anna could admire her sister without getting caught. Anna stared at her sister as she was pleasuring herself. She was quite muscular, Anna had to give her that. She was mesmerized by the way Elsa's ass clenched whenever the icicle was thrust inside her. Sweat beaded on her forehead and ran down face to her neck, finally dripping to the ground off of her nipples. Elsa's breasts we heaving up and down as she was breathing very rapidly. At this point, if she was being completely honest with herself, Anna was quite turned on. She lifted her skirts up and slid her panties to the ground. Anna began rubbing her clit violently. Elsa was still oblivious to what was happening outside the bathroom door. She now arched herself backwards and Anna could see the water from the icicle dripping to the ground. Elsa shoved her breasts at the ceiling, and Anna got a good look at her erect nipples. The got Anna's heart racing faster and she started rubbing herself more rapidly. Her fingers were soon wet. At that moment, Anna gasped. She didn't mean to and she immediately chastised herself for doing it. However, Elsa didn't seem to notice, probably because she was moaning at that moment. Anna went back to masturbating and soon she could feel a moan coming on. She held it in for a while. She watched Elsa arch her back again and open her mouth. She was going to moan again. Anna figured this was her turn to let it out, hoping to time it right with Elsa. Unfortunately for Anna, Elsa didn't moan. Instead she turned around to see Anna standing outside the bathroom door. "Anna!"

Anna tried to maintain her cool. "Hey Elsa. I was just waiting for the bathroom."

Elsa was not convinced. She looked down to see Anna's panties lying on the floor. She pointed to them. "And how do you explain those?"

Anna stammered. "Well...uh...you see...uh..."

"Anna!" Elsa, who was still naked, chased after Anna. Anna ran as fast as she could, leaving her panties behind. Anna had a head start, but sure enough, Elsa caught up to her. "What did I tell you about doing that?"

"To not to," said Anna sheepishly.

"So why were you doing it?" said Elsa.

Anna looked at her feet. "'Cause I enjoyed it."

Elsa screamed and pushed Anna up against the wall. "You are never going to do that again. You got that?"

"Yeah," said Anna. "I'll never let you catch me spying on you again."

Elsa grit her teeth. "I'm serious, I never want you to do that again, or else."

Anna laughed. "Or else what? What're you going to do to me?"

"This." With a snap of her fingers, Elsa conjured an icy chastity belt around Anna.

Anna looked down, staring at her sister's handiwork. She was practically stunned. After a while, she spoke. "What did you do?"

"What I told you I'd do," said Elsa. "Make sure you'll never do that again."

Anna pawed at the contraption, trying to get it off, but it was no use. The chastity belt seemed molded to Anna and would not budge. She wondered it the heat from her hands might melt it off. Anna rubbed her hands together, trying to generate enough heat to melt the ice, and pressed it against the chastity belt. She held her breath, hoping it would do something. Unfortunately, it did nothing. Not even a lone drop of water dripped from it. Anna slammed her fist against it in a last ditch attempt to break the belt. As with before, this did nothing. Anna looked up at Elsa. "You bitch! How am I supposed to come?"

Elsa smiled. "You're not."

Anna growled. "I will get back at you for this."

Elsa laughed. "And how do you plan to do that?"

Anna grinned. "If I can't come, then you're going to have to make it up for me."

"What are you...hey! What are you doing?" Anna grabbed Elsa by the waist and flung her over her shoulder. Elsa kicked and punched her sister, but Anna could not be stopped. "Put me down! Put me down right now! Where are you taking me?"

"Oh you'll see." Anna took Elsa to her room. When she got there, she tossed Elsa to her bed. Elsa tried to run away, but Anna pinned her to the bed and took out a pair of nipple clamps, which she put on Elsa. These clamps completely immobilized Elsa. Anna smiled and headed over to her nightstand. She opened the drawer, which contained a fairly sizeable collection of vibrators. Anna selected two and went over to Elsa. She held them out for Elsa to see, allowing her to hear their buzzing. Elsa gave her sister a look of horror, which Anna responded to with only a mischievous grin. Anna shoved both of them inside Elsa. Elsa's legs shot up as the vibrators entered her. They flailed around wildly, threatening to hit Anna in the face. Anna back off a bit, but still continued with her assault. Soon Elsa came. She through her arms to the side and screamed. Anna paused for a while, laughing at how ridiculous her sister looked, but she went back to shoving the vibrators back into Elsa. Elsa struggled again, but with not as much effort as before. Again she came and again Anna laughed at her. And again Anna shoved the vibrators back into Elsa. The cycle continued five more times. Anna was about to do this for a sixth time, when she made eye contact with her sister. Elsa gave Anna a look that just begged for mercy. This gave Anna pause. She dropped the vibrators and thought about it for a moment. Finally, she walked up to her sister and undid the nipple clamps. Elsa got off the bed, rubbing her nipples. "Elsa, are you okay?"

"Yeah, never better." Elsa proceeded to hit Anna with a blast of ice knocking her back to the wall.

"You bitch!" said Anna.

"Payback's a bitch." Elsa froze Anna's mouth shut, making a hood over her head. Elsa bound Anna's legs together and started binding Anna's arms to the wall. Anna struggled against the restraints, but they were to strong. At this point, Anna came up with an idea. She still had the nipple clamps in her hand. She looked at Elsa's nipples. They were still red and erect. Anna smiled. With the little movement the restraints allowed, Anna threw the clamps at Elsa. Elsa saw this and tried to stop the clamps, but it was too late. Her eyes widened as the clamps closed in on her nipples, immobilizing her. Anna smiled to herself as Elsa collapsed to the bed. She then began to try and free herself from the ice. She pushed against it experimentally, and thought she could wiggle out of it. She then pushed against the ice with all her might. It did nothing. She tried again, but to no avail. She looked at Elsa, who was the only one who could free her. Elsa only gave Anna a smirk. With the nipple clamps on, Elsa could do nothing. Anna was going to be stuck here for a while.