Naturally.

You groan in triumph as you come, your thick, virile seed poured right into your sister's spasming womb thanks to your length. You hold yourself tight against her, panting as each spurt guarantees that your sister's become your little seed bed. You grind slowly against her once you're done, feeling her come again despite herself as you whisper. "Oops! I came inside." You stir your seed inside her, holding yourself against the entrance to her womb, smiling.

"You're not going to be a little bitch anymore, are you?"

She shakes her head, sobbing. "Good. But just to be sure- you're not going to tell anyone about this, or about anything else I decide to do to you. You're also my own, personal cumdump from now on." She sobs, will broken. You pull out of her, make her straighten herself up. Another murmured command makes her face dry and devoid of tears, back in its usual bratty attitude. You smile at her. You release the stopped time, and eat your dinner with hearty relish. You wonder if the fact that you don't feel guilty means that you're broken. Well, absolute power, you guess. Might as well enjoy it.