After you and Lydia climax, she slides off you and your tails instinctively uncoil. Exhausted by your lovemaking, you take Lydia in your arms and relax in the jacuzzi. You soon feel your tail slowly seperate back into your legs. After a few minutes, everything seems returned to normal.
You begin to doze off when a thought crosses your mind and jolts you back awake. Hurriedly you pull your swim trunks off then grab Lydia's bikini bottom and yank it off.
"Hey!" Lydia exclaims, caught by surprise and clearly jolted out of almost nap of her own.
Recovering her bearings, she changes her tone. "Ready for another go already?"
You're tempted, but you still feel spent. "Not just yet. But I realized if we're going to stay in here we'd better get out of our swimsuits or we'll start turned back into mers."
"Oh." said Lydia. "Yeah, I guess so."
"What time is it?"
"No idea."
"Not that I'm in any rush to get out of the jacuzzi" said Lydia regretfully "but we should probably pick up our clothes before my parents get home. I haven't told them about..."
"...any of the recent developments in our relationship?"
"Yeah. I'm not sure which part might freak them out more."
"The jacuzzi" you offer. You both laugh.
Lydia gets out of the water first. You get a nice look at her backside and realize something.
"Lydia..."
She turns around. "Yes?"
You enjoy the view for a moment. "I realized this is the first time I've actually gotten to see you naked. When we've had sex before you always had a spandex body. And afterwards you had changed into fresh clothes by the time I woke up."
"You probably liked it better that way."
You get out of the water and take Lydia's hands in your own.
"This is your real body and it's beautiful."
"Thank you." Lydia kisses you. The feeling of her body against you reminds you of something else you've noticed.
"I think your breasts may be permanently larger."
Lydia looks down and lets out slight gasp of surprise. Her normal A-cups had expanded each time she transformed, but both times before had returned to normal when she changed back. Now...well, they weren't as big as they got when she became a mermaid, but they were definitely at least B's now.
Lydia sighs. "That's going to cut into my swimming speed. I guess that's what I get for going topless."
She notices the grin on your face. "Not that you mind" she says and gives you a playful elbow to the ribs.
Lydia grabs a pair of nearby towels and gives you one. You both dry off before you collect the discarded wet clothing and swimsuits from around the jacuzzi and Lydia gathers those by the front door. You both head upstairs and hang up the wet clothes in Lydia's bathroom before sitting on the end of Lydia's bed.
"So was it everything you'd dreamed?" you ask.
"It was pretty good" admits Lydia with a smile.
"I guess we both need to be careful about swimsuits now. At least I'd assume 'temporary' will be as temporary for me as it apparently is for you."
"And if either of us ever sees a genie just tell him no thanks and walk away!"
The two of you share a good laugh at everything that has happened in the last week, brought closer by your shared mistakes and misadventures, fears and fantasies, and intimacy.
"I love you, Lydia."
"I love you too."
The two of you share a long, passionate kiss. Followed by several more.
"You know, we've never actually had sex when we're both fully human."
Another kiss.
"Probably not as good" Lydia says with a smirk.
Another kiss.
You fall back on the bed and pull Lydia down with you.