“Actually I know something I think you’ll like” Claire stated right as Mavis was about to make a suggestion. “Oh... go on then” Mavis accepted as Claire closed her eyes to think while stripping off her clothes. “Oh I best also get naked” Mavis noted as she followed suit.
But once Mavis was halfway done she then saw the changes as Claire thought about them while sitting down. Claire’s legs started merging into a single limb while her toes grew and split into branches while a transparent membrane grew among them. Then everything from Claire waist downward started having silver scales popping up while Mavis caught a glimpse of a fin-line appearing down the back of Claire’s tail.
“Well... what do you think of your mermaid mother-” Claire started once her change was done only to notice something “WHAT HAPPENED TO MY CHEST?” over how bare her breasts were. “That’s a childish TV thing mum. There are many depictions of mermaids being nude” Mavis assured while crawling closer. Claire noticing that Mavis was undergoing a similar process she had gone through into becoming a mermaid...
...only Mavis was also shrinking as she de-aged “I think it’s best you follow to how old you were when I was originally inside you” she suggested while pulling herself onto Claire lap. “Mavis I doubt-” Claire started only to feel something forming inside her. Then watched as some umbilical cord-like thing burst out of an until now hidden hole in her tail and link up Mavis’s belly button. “I really like to try out being a mermaid this whole trip but start it unborn. If you know what I mean mum” Mavis explained as she closed her eyes right before she reached the point she couldn’t speak.
From their Claire could only watch and think, unaware that as a side effect of the obvious changes happening to her that as a result of Mavis’s words she was de-aging herself back to her early 20s. Meanwhile the calf in her tail grew huge briefly as a now sleeping baby Mavis was pulled inside which resulted in Claire belly expanding until she was looking like she was about to give birth while the calf hole closed back up.
“God Mavis what were you thinking?” Claire snapped while looking at her stomach while had gotten slightly smaller. “Come on mum. How often does one get to try something so rare” Mavis’s voice suddenly said in her head. “? How are you-” Claire questioned. “Manual said those that un-birthed themselves are mentally linked to those chosen to bare them” Mavis answered “So what are we doing for the next few days before I come back out?”. “Really going through this aren’t we” Claire accepted while the room shifted in design to accommodate the changes: