an explanation

You sat on your parent's bed wrapped in towels waiting for your bodies to dry enough for your tails to revert back. Your mum had a towel wrapped around her hair but her chest was as bere as yours with her D cup breasts sagging on her chest. While cleaning each other and crawling to the bed you had noticed a few key differences between your mum's full mermaid body and your half merman body. Your mother had a fin that ran down her spine from the base of her neck to the tip of her tail, it was the same orange colour as her fluke that was solid like dolphins but had raised ridges. Your fluke was transparent and you could see the non-transparent outline of your feet splayed out inside. It was if your transformation was less complete.

"So 2 out of 4 isn't bad." Your mum remarked. "Your other brothers inherited my sirens genes from their great grandmother. How the half-bird part would manifest I don't know. Sirens tend to eat humans rather than mate with them but they boys have their charms" She added. Referring to your brothers as "the boys" who had been almost inseparable until the virus. You had been jealous of the ease they seemed to have with women compared to your bad luck. "Your sister, of course, inherited the mer gene she discovered it when she went off on her gap year." Your mother added.

"So, is there a way to control my transformation as you do?" You ask.

"With practice, you can make it easier to induce and now you know how to embrace the transformation instead of rejecting it like when you were diving. But no, Half-mer can't change at will." Your mum explained. As she did this her tail began to split and turn back into legs.

Moments later you felt the pain of your tail splitting as if someone had used double-sided duct tape to stick your legs together and you had to rip your leg hair out to pull them apart. "AAAAAAAAAAAARRRRRRRRRRRRRRR!" you cried out in pain.

You mum pulled you into a hug. "It's alright baby, mummy's got you." She soothed. "Now we have our legs back let's clean up the bathroom and I will answer your questions."