Not very

As soon as the warm sensation hit her ankle, Samantha gave up, not wanting to take the risk of finding how long she could last. "Please stop, I give up, you win. I'll do whatever the sisters want me to do, just please undo what you did, I don't want to die." She yelled out scared. Justin moved back slightly and sat up, "You're no fun." He said to her, "However, if you can't take this, then I doubt you'll be able to handle anything my mother's throw at you." He continued, moving forward and lining up his now erect dick to enter Sam. "Wait, what are you doing? I thought you were going to release those blocks you put up once I gave in." Sam asked as he saw what Justin was about to do. "Originally, yes. However, since you are nowhere near the standards my mothers hold, there's no reason to keep you around, so I'm going to fuck you until either you die from the sheer pleasure or until I decide to release the blocks, and the orgasm kills you."

Sam went to scream out "Wait!" but before she could, Justin thrusted into her, sending a shiver down her spine, and the warm glowing feeling half way up her calf. With every thust, the warm sensation went up a few inches, and while she wanted to do so many things, like try to escape, scream, cry, beg, plea, anything, all she could do was moan in pleasure, and seem to thrust her hips up to meet Justin's, it was as if the pleasure set her body on auto-pilot. As the feeling went up and past her hips, the feeling of Justin's dick in her changed. Before, it felt like a hot fleshy tool pleasurably pounding into her, now, it felt as if a glowing rod of light was being thrust into her and it made what he was doing feel slightly greater.

As the glowing sensation moved closer, she found it tougher to think of anything else but the pleasure she was getting and sex in general. Once it went past her stomach, and started to cover her breasts, it seemed what she wanted to do and what she actually did diverged greatly. Justin released her frozen limbs, unbinding her, and instead of making an attempt to run, her body, which was all she could think of it now since it acted on it's own, pushed herself up and wrapped her arms around his neck and legs around his waist. Although she wasn't sure, she although think at one point she actually started talking dirty to him. She wasn't sure if he was doing this to her, or if all the sex had just released her inner sexuality, and the part that was thinking right now was just some small subsect that yeilded no control over her body, but she wished she could stop this. As she started to lose feeling in her neck, Justin and her body started kissing and making out while fucking. "This couldn't have happened at a better time" Sam thought to herself as she lost all feeling in her face, as the glowing sensation started there, slightly happy she didn't have to actually feel herself kissing the man trying to kill her, although she could still see it. Once all feeling was replaced in her body by what Justin had described earlier, she knew her sight would be the next to go.

At first, she thought it had gone quickly as she saw a bunch of white light, but soon realized that Justin had orbed them to fuck her against something. As her body started to lay down again, she saw that she was currently in a sex swing. Where they were exactly or why that, she didn't know, but Justine seemed to know how to use it with a woman well, and her body seemed to be crying out in sheer pleasure. It took only a few more seconds for the next level to be reached, as she started to notice how what she saw was fading out, and what could be described as a bright white light was fading in. It was happening slowly, but at a steady pace, and it wasn't long before all she saw was the white.

Finally, she could hear all the noises her body and Justin were making faded out, and a chorus of tones started in, which sounded beyond anything any human could hope to do on their own. At this point, Sam completely gave up, knowing it was the end for her. All she could do was hope that somehow she survived, and if she did, she'd somehow be able to escape.

Justin knew exactly what was going on, using his powers to sense how far Sam was into the entire thing. It was at this point he decided to finish what he was doing.