John was shocked at the sudden appearance of breasts on her chest, but not for long, as Emily had soon wrapped her lips around one of his nipples and started sucking greedily. John moaned in a new melodic feminine voice. It sounded lovely to her new finned ears, and they wiggled happily on her head.
John hadn't noticed yet, but she was already thinking of herself as a woman, and being stimulated sexually like this was rapidly making her mind more of a mermaid. Her tail waved gently as Emily kissed down her tummy and towards her new fishy pussy.
As Emily plowed her tongue into the newly minted mermaid's slit, John started to change further. Her breasts blossomed from mere bumps, to apples, to oranges, with a pair of dark brown nipples rock hard with arousal. John reached down and rubbed them as she was getting eaten out. The hair on her head poured outward, lightening to a golden blonde, streaked with violet to match the scales on her new tail. Her webbed hands became scaly. Those scales grew up her wrists and forearms, while two spiny fins emerged from those same forearms.
It wasn't long before the tongue plunging into John's cunt drove her to orgasm. He moaned and shrieked with delight as he came for the first time as a mermaid. They wrapped their tails around each other in a mermaid cuddle, not caring about anything else in the world.