As you stare into the water, beautiful and pure-looking, you suddenly get the urge to drink some. You know in the back of your mind that that's a terrible idea- lake water is usually polluted as hell. But you get on your knees anyway, and put your head next to the water, lapping some up. It tastes wonderful, cool and fresh like the most expensive purest water you'd find in a store. As you exhale happily and wipe your mouth with your hand, you realize your skin feels softer. When you look in the water again, your lips look a little different, and as you feel a weird tingling spread through your face, you look in the water and realize your face is changing. You gasp, but then suddenly feel good.
Unbeknownst to you, the water has seeped into your pituitary gland and is affecting your hormones, changing your sexual responses and making the changes start to feel really good. You pull off your T shirt and watch your nipples enlarging, panting as the tips swell and become sensitive. Your cock turns hard as you watch your torso reshape itself, your waist narrowing and budding breasts rapidly growing on your chest. After pulling off your jeans, your butt and hips round and widen to feminine proportions and your legs turn more lithe and smooth. Your body looks totally feminine in every aspect except the hard penis between your legs, and to your surprise, you lick your lips as you feel it start to change.
You let out an involuntary soft moan as you feel your feminized body seize your testicles, and as they pull inside you you feel a sense of relief as the weird pressure in your crotch subsides. Looking at your changing crotch in the water, you see the skin's texture and shape change as it goes from being a skin sac to an almost flat mound. Your penis pulses as you feel it start to reshape, pulling back into your body, and as you rub it the sensations become more intense and centred around the tip. While masturbating eagerly, jacking off and rubbing your breasts together, you feel your mound start to become sensitive, and you take your hand off your shortening shaft and start to rub along your forming pussy lips while your thumb continues to massage your tip, which is rapidly becoming your clitoris. Once your vaginal opening forms, you gently push your fingers inside it, and the feeling of taking something inside your body makes you cum almost instantly. Your passage clenches around your fingers, your clit pulses against your thumb and your nipples shiver in your hand as your previously male body experiences an intense female orgasm.
You look in the water again and see the face of the woman you saw before you drank the water. You're a woman now... but why?