Right now, I have quite a bit of free time, so I'll try to post every 1-2 day(s), but I know that it's probably not that sustainable. For now, expect weekly updates at the slowest, I guess.
Alright, you think, alright. The first thing that you need to do is to calm down. If you're panicking, you'll just make a fool out of yourself, and that's not becoming of a mysterious youkai like yourself.
First, you close your eyes. Then, you take a deep breath and hold the air in for a couple seconds before letting it go. That might sound like a stupid thing to do when you don't even have a single lung beneath your neck, but the fact of the matter is that you don't really feel any difference in breathing whether your head's attached or not. While there must be a perfectly good explanation to your anatomical peculiarity, you're neither a scientist nor a magician nor a nerd, so you've never thought about it too deeply. You usually just chalk that up to your rokurokubi/dullahan greatness and call it a day.
At this moment, though, you wish that you can keep distracting yourself from your current predicament with idle thoughts like that. Your mind keeps returning to your missing body, but because you still have no idea on what you're supposed to do, you continue your meditative breathing session. You take another deep breath, hold it in, and let it go. You take another--
"Wow, is that—is that a head? Are we going back to human sacrifice, now? Gross."
A faint smell of sweet potato wafts through the air. You open your eyes and stare straight toward the face of an equally surprised girl hovering above you. Her short, blonde locks hang down from her hat. She looks like a prim-and-proper lady from a good household somewhere, what with her poofy blouse and fancy apron, but you have a feeling that she's not an ordinary person.
"No one should be able to sneak on me like that," you said after putting on enough airs. You quietly decide to not bring up your own effort of self-distraction. "Who are--"
are you?" She cut into your words. "Humans can't talk with their head cut off, can they? Are you some kind of youkai?"
"...Well," you started again, feeling a little miffed. "My name is Sekibanki, the rokurokubi--"
"Oh, wait, wait. The youkai that can detach their heads?" You sigh, roll your eyes, and nod—although that just causes your head to dangerously tilt in place. "Whoa, hey, careful!" Of course, she consequently reacts by reaching out and holding you by your cheeks. You're not sure on what to feel. The thoughtless girl's hands are pressing annoyingly hard against your face, but her short fingers still feel smooth and cool to touch... Although that might just be due to the hot blood rushing to your face.
Again, you don't know where the blood comes from. Now that she's picking you up and holding you at arm's length like some toy, you're not in the condition to ponder it, anyway.
"L-let go of me!" You shout. This is too humiliating. As she lifts you up, head and cape and all, you realize that you're completely helpless in her hands. You can't even move your eyes from her face and her breasts—which actually seem bigger than you first thought, now that you get to look at them from this angle. Her clothes might be a bit too loose for you to be sure, but from the way her arms squish against their sides, you assume that they must be quite soft too--
"...harvest." Damn it, she was saying something.
"W-what? Please repeat that... and put me down, already!"
"...Hmph." She frowns. "You should stop being so insolent and pay attention when a deity speaks. I'm Minoriko Aki, the goddess of plentiful harvest. Didn't they at least tell you to whom you're being sacrificed?" Is that why she smells like sweet potato? You really want to point out just how weird that is, but you have other, more important stuff to say.
"I'm not a sacrifice, and I have nothing to do with gods or worship or whatever! Just put me down--"
"Huh..."Well, I guess it's rather strange for the sacrifices to start this early..." For someone who just told you to pay attention, she sure isn't interested in everything that you have to say. As she continues to look up and stare inquisitively at you, she starts to walk, and you begin to wonder if a goddess can truly be this scatterbrained.
No, it's even worse. As her hands are suddenly released from your head, leaving you to hurtle down toward her face at a distressing speed, you manage to figure two things out: Minoriko has tripped, and she's proven herself to be a bigger ditz than you thought.
You feel the impact, and everything fades to black.
"...Ow," you groan, and reach up to rub your forehead. "You clumsy idiot...!" You yell at Minoriko. Although you're not hearing any response, you can still smell the scent of sweet potato, so she must be close by. You figure that she's either silenced by her guilt or knocked unconscious by your head.
...Yeah, it's definitely the latter. It hurts quite a bit, so it's not that unreasonable--
Wait. How are you rubbing your forehead right now?
You hurriedly hold your hands out. Your palms and fingers are shorter and thicker than you remember—but they seem all too familiar. They end in yellow, poofy sleeves that are covering your arms. You have a bad feeling about this. With a gulp, you prop your torso up with your elbows, and shift your gaze downward.
The heaving mass beneath your red dress is rising and falling with your every breath, and it's obstructing your view to the rest of your body. Breasts. You now have a large pair of breasts, and they're quite more than a handful—certainly more than the extent of your new hands. To test that, you place a trembling hand on one of the bounteous pair, and squeeze.
Your hand has to go through a few layers of clothings, but you can feel the soft, yielding sensation on both ends. Your breath escapes your lips in half-gasps. You never knew you have this power, but it seems that you now have Minoriko Aki's body as your own. Now what?
 ...You have to investigate closer! Strip down!
-  And pleasure yourself!
 You have to find a place that's safer and more private first!
 T-this is too weird! You have to try to undo this!
The first choice(s) to three will continue the story.