I can't remember the exact moment my love for my mother turned into lust. I was a kid only just starting to grow into a man when I noticed how beautiful my mother was. Her long, dark hair shone, her face was gorgeous, and her big brown eyes were bright when they looked at me. Her slender body was always tied up in a kimono, but it was easy to see the curve of her hips and breasts when she wore them. My guess is that her breasts are just under the size of her head, likely the biggest in our village.
We live in a small town named Miyogi in Japan. My name is Sato Takahashi. My mother, Shiori Takahashi, and we have lived together in a small house with a large garden a short walk outside the town proper for all my life. My father left town soon after my mom became pregnant with me, but she has been content with raising me alone after the villagers collaborated to build a house for her. She sews kimonos for the people in town, and has a stall in the town's center to display and sell them.
The most recent event to have spurred on my lust must have been in the summer of last year, when I saw her masturbating. I was in the bathroom across the yard from the house when she returned home. I was 18, my birthday earlier in the spring, and spending my days doing little else besides taking care of the garden, masturbating, and going out to the woods with friends. She called for me, and I stayed silent, the bathroom door closed; there was a crack in the wood of the wall, though, and I could see most of the house from there. I saw her enter the house and heard her run into her room. She slid open the door that led outside from her room, looked out to the yard, and immediately began stripping. With the door still open, I had a perfect view as she sank to her knees and fingered herself. It was difficult to ignore the sight of her body and the sounds of her moaning, so I masturbated with her, keeping quiet in the outhouse.
From then on, I was completely infatuated. The next year, when I turned 19, I must've jerked off at least 5 times every day. As far as I know, my mother has not masturbated at all since that day last summer, but it was and still is great to reflect back to that day whenever I want to jerk off. Though I certainly did want to fuck my mom, it didn't seem like it would ever happen until I found the oppahana.
I was bathing upstream one day when I saw a plant I didn't recognize. It was a thin, many-branched and bright green plant with tiny red flowers. I picked a stalk and brought it home with me, and took it to the village elder later that day.
"Well, it seems you are the luckiest one of your generation!" the old man said as soon as a showed him the plant. "That is the oppahana. It grows only near the waters of this village, and is a gift from the god of our shrine. Once every generation, the plant shows itself to a young man; it has great magical power!" The elder pulled open his robes.
After I got over the initial shock of the flabby wrinkliness of old age and the fact that the village elder just flashed me (thankfully inside his home), the aftershock hit. "Your penis is huge!"
"Yes it is. The oppahana enhances the sexuality of anyone who consumes it. You would not remember my wife, since you were only a small child while she was alive, but she had the greatest tits in the world! They eventually got so big, it was tough for her to leave the house!" The elder gave me a big smile. "I miss those days, when I could actually get my damn cock hard."
I cleared my throat, more than a little creeped out already by the elder who had given such sagely advice on difficult life matters to me previously. "So I just chew on this plant, and my penis will get bigger, and if a woman eats it, they will have larger breasts?"
"It's not just boobs and dicks, Sato! The plant will make you more, shall I say, amorous, and will also have an effect on the rest of your body. You will be stronger, healthier, and more attractive. It truly is a miraculous plant. Also, instead of just eating it, I recommend drying it and making a tea with it, 4 parts regular tea leaf, 1 part oppahana. It tastes rather nasty."
"Thank you, village elder. I'll thank the god of our shrine on the way back home." I bowed to him to make my exit.
"Before you leave, though, might I ask who you will give the plant to? It only works on one man and one woman."
I grinned, and said, "I'm not so sure yet, but I have some ideas." Of course, it was obvious who I'd be giving the plant to.
So I searched all the rivers and streams around the village for the next few days. Surprisingly, I found the plant almost every place I went to, and gathered enough of it to last me a lifetime. Since my mother was always busy making or selling kimonos in town, I had plenty of time to dry the plants in secret and masturbate to the thought of us growing together. I already made the tea and the meals at home, so she wouldn't suspect a thing.
I tested the tea myself first. One part oppahana, four parts tea leaf from town, one cup every day for a week. At the beginning of the week, I compared my hard cock to my hand; it reached from the bottom of my palm to the tip of my middle finger. I didn't even notice a change in the flavor of the tea. And it might just have been my excitement about trying it, but I swear I was hornier and hornier every day. That whole week, I jerked off around seven times every day.
I measured myself the next week. The whole head of my cock was past my hand! Either I had grown considerably, or my hand had shrunk; I had my money of the first possibility. And so, I started putting a dose of oppahana in the tea pot.
For a while, nothing changed. At least, not for my mom; my cock continued to grow, and along with that, my loads became bigger. I used to cum inside of a pot while I was home, and empty it out in the nearby stream at the end of every month. Now I had to empty it every two or three days. Not only was I cumming more, but I was masturbating more too. My cock was nearly as long as my forearm by the time my mother changed.
I remember that night very clearly. I hadn't been able to sleep because of the wind outside, and by the time it calmed I was still wide awake worrying about when my mother would start to change. Then I started to hear some noises from her room. I carefully stepped to my door and slid it open to the short hallway, and crept to the end where my mother's door was. Behind the door, I could hear my mom fingering herself, trying hard to keep quiet. I stood outside the room and listened closely, resisting the urge to jack off right in the hallway.
After a few minutes, she orgasmed. For a few minutes, she orgasmed. Continually. I had watched her last year closely, and she had cum then for only a few seconds, and then immediately gotten dressed again. Tonight, though, she was doing nothing but cumming, moaning very loudly. I had to run back to my room and cum three times before I was soft again!
The next morning was when I got to see the changes for myself. I came to the kitchen for breakfast and saw my mother from the back, wearing a men's kimono, her black hair reaching the floor. The kimono was big and dark green, and I was wondering why she had it on until she turned around. Her tits! They were huge! Last night, she must've gotten all her growing from the past few weeks done. I deduced that the growth only happens after you cum, a guess that proved correct later. That explained her hair, too, and why she looked so much cleaner and brighter than usual. Her face was shining, her smile was dazzling, her tits were bulging, and her hair was long and lustrous.
"Good morning, Sato."
"Hey, mom. Um, you look different..."
