Why the fuck does you sister have panties on in the shower? Dude. For real. Also the dialog doesn't match up with the first sex scene happening ONE night ago. It would be more like "I've been thinking about nonstop all day" not "thinking about it every night since." You might want to make a flow chart or something of the timeline. A summary for day 1, day 2, etc. to keep it all straight.
Last thing. I just wanted to suggest something to add to the corruption. MC can strategically use his love as positive reinforcement after his toys play with him. Kisses, "good girl", playful butt taps to reinforce their place at his side. I mean I don't know how evil and manipulative you want to make him but you could have him monolog about how twisted doing it on purpose would be. Reward servitude to sink the hooks in deeper.
Last thing. I just wanted to suggest something to add to the corruption. MC can strategically use his love as positive reinforcement after his toys play with him. Kisses, "good girl", playful butt taps to reinforce their place at his side. I mean I don't know how evil and manipulative you want to make him but you could have him monolog about how twisted doing it on purpose would be. Reward servitude to sink the hooks in deeper.