You try your best to get back to the shore, but you're too late. A hand grips your swim trunks and forcibly pulls, leaving you naked. You freeze in shock, and turn to see a beautiful mermaid. She looks immaculate, her face so pretty and her bare breasts so supple, and as she wraps her tail around you, pulls your mask off and kisses you, you feel an intense desire for kinship with her.
As she breaks the kiss you notice your face feels tingly, and it slowly dawns on you that she's starting to change your body. You hear a question, not sure if it's in your head or she actually said it to you: "Would you like to join my sisterhood?"
You do everything you can to reply yes, and she answers, "Then I will grant you womanhood". Intense shivers run through you as you seem to change more. She kisses down your body and your notice you seem to be growing more petite and curvaceous than normal. She licks and sucks on one of your nipples, then the other, and you moan silently as she does and then massages the erect nubs. Around them soft flesh swells, growing so large and sensitive, and you look with a sort of pride at your newly formed breasts.
Now you feel her hand move to your crotch and your arousal mounts further as she strokes your hard cock vigorously. She rubs one of your nipples as if to remind you of the contrast between masculine and feminine pleasure, and you hear her say, "release your manhood's seed so you may embrace your womanhood!" You do as she asks and cum hard, white seed flowing freely from your cock towards the surface until you're spent. She moves her hands to reshape your crotch and you feel her wean away your penis into a clitoris, while she pushes your testicles inside you and reshapes them into ovaries, and makes a slit leading inside you which forms your vagina.
You look at her cute smile in amazement and realise you are like her now. Next, she...