Rarity has done many horrible things. Violent, blood filled things.

But when it comes to thoughts about her sister she can't imagine it. Her thoughts for Sweetie are much kinder, softer and loving.

As much as she wants to enjoy her sister's body she doesn't want to ruin what they have.

But, she can look right?

[Futa/Sleep molestation and mentions of gore. None happens in story. Sweetie is NOT a minor here]