No, she is none the wiser

"You're sitting awfully close together aren't you?" Monica said

Melody didn't say anything, presumably because if she did, her voice would give away what we were doing.

"Well Melody was a bit cold" I responded so Melody didn't have to.

"Wow didn't realize you two were so close, I meant close as in close friends not psychically close" Monica continued.

"I always was good at making friends, you know" I responded to Monica while I slipped my hand under her sister's panties. The moment my hand made contact with her raw skin she twitched slightly but not enough to raise suspicion.

"Anyway what movie did you guys pick?" asked Monica.

"Just some rom-com" I said, "It seemed decent enough."

"Okay sounds good," said Monica and sat down on the couch.

Meanwhile my fingers found their way inside Melody's pussy. Luckily Monica doesn't notice due to Melody being a good girl and keeping quiet.

At first my plan was to edge Melody through the entire movie but seeing Melody adorably trying to suppress her moans and twitches from her beloved sister made me just want to make her work harder to hide it. For a second, I remembered that I also didn't want Monica to notice me finger her sister, however my lust was greater than my willpower today.

Against my better judgement, I started fingering Melody harder and harder.

I felt her breathing get heavier and heavier. Both her and my body got hotter and hotter, making it really sweaty under the blanket. I felt her quivering, twitching and writhing in pleasure as she got closer and closer to cumming.

For a moment, I felt her entire body tense up only to go limp when she came.

Through the rest of the movie, Melody didn't say a word so instead I and Monica were the ones talking.

When the movie was over, Monica decided to go to bed which was understandable considering her week had somehow been busier than mine.

As Monica got up and started getting ready for bed, I realized that Melody was still planted firmly in my lap. This got me thinking about what I should do next?