Time Paradox

I decided to flesh out a vague scenario I've had in my head for a long time now. Enjoy.

One brief explanation might be needed: the "dream narrative" is, well, you know when you're dreaming and you know what something is without anyone telling you? The dream narrative is the mechanism that automatically explains things in your dreams. That's all.

Rachel laid her head down and fell asleep, lapsing into a strange dream. In it, she was lying in bed in the same position, presumably having just woke up just past midnight. Sitting up, she saw the moonlight cast through her window falling across a voluptuous figure she knew she recognized. Her dream narrative told her it was...herself?

Laughing softly, she explained, "Yes, just as you thought, I'm you, but not quite." Stepping forward into the better part of the moon's rays, Rachel looked her over and saw she was a bit taller, had a bit more bust, had shorter hair, and was overall thicker and curvier. All of her showed signs of aging, and Rachel thought she had aged very well. Except for one detail that was off...Rachel saw the wrong set of genitals sticking out from between her double's legs. "I'm you from the future. I changed my name to Razel, and became a lot more sexually active. But I wish I'd gotten started sooner, so...I'm here to break you in." The future? Why did she get a cock? Was it grafted on? A mutation? She'd never thought about having one, ever. It couldn't have been a conscious choice. It must have taken over her entire thought process, and now...

The realization she was about to be raped set in, and she tried to leap from the bed, but something akin to sleep paralysis set in. Her dreams were mucky like that. Razel had already straddled her, but wasn't getting ready to do the deed just yet. She leaned down and planted a smothering kiss on Rachel's face, finding the other tongue and shoving it around forcefully. Rachel relented and decided to go along with it, since this was an inconsequential dream anyway and couldn't escape her virtual rape anyway. She caught on and learned how to make out with herself almost right away, taking turns exploring Razel's mouth and letting hers be plundered. She was already moaning and vaguely thrusting her hips up at Razel, looking for that erect cock, but she was still sluggish from paralysis. She tried lifting her free arms from her sides, the dream allowing her to overcome the paralysis slowly. The slow motion only added to the intimacy as she clasped her left hand to her own breast and her right hand to Razel's, simultaneously comparing and stimulating them. Razel moaned encouragingly and sank her body lower to Rachel's, every part connecting perfectly, skin rubbing against flawless skin. Rachel could feel Razel's erection prodding her mound gently, but not entering yet.

Rachel broke off the kiss and implored, "Just hurry up and do it." With unexpected violence, Razel grabbed her arms and held them down, Rachel