"Um... ok. Maybe after dinner in my room before the cam session?"
"I was thinking more like now, out on the coffee table again."
"In front of you?"
"Yes, I want to see how you're going with the bat. Maybe try lots of baby oil again?"
Casey was shocked that she'd have to do that in front of her sister, or that Jolene would be at all interested in watching. It was bad enough doing it for any audience, but an audience of one was somehow worse, and an audience of one who you were related to was ten times worse than that. Her skin crawled at the thought. Nevertheless, it was an order, and as an Indent she knew she couldn't refuse it.
Soon she had her body covered in baby oil again and was inserting the dildos one by one. Even the "smaller" ones felt huge. Finally she had the largest one in again. It was slightly easier this time but still took some effort. Casey thought it was more the technique that she'd learned rather than any change in her anatomy that allowed it to go into her.
Jolene kept watching and instructing her to put her legs further apart, hold the dildo from behind so her hand didn't block the view of her pussy, lean back further and so on. Casey realised Jolene wasn't watching for her own gratification but was instead teaching her how to perform. She didn't know if that was more humiliating or less though. She was still totally naked and openly displaying her hairless vagina to her sister while inserting large objects into it, and now she was about to have an orgasm!