Okay, so this one needs a bit more warning than my other stories.

Basically: if you didn't notice earlier, this is M rated for strong language and strong sexual content between 16- and 17-year-olds. While I am shooting for M and not MA/E, I'm a bit fuzzy on exactly where the line is.

Anything necessary for following later stories in the timeline that shows up in this one will be described later as needed. I do not intend to make this required reading to follow future stories.

Pairings: Phineas/Isabella as the primary focus, with Baljeet/Ginger and Ferb/Gretchen as secondary. Candace/Jeremy, Django/Adyson, and Buford/Milly show up in the background. (I'm using the pairings from Lowrider's "Summer of Love", but not necessarily the same way.)

Timeline: June/July of the summer between junior and senior years of high school. Two years after Back in Time for Dinner; about a month before Founding the Foundation. Isabella, Baljeet, Ginger, and Gretchen are all seventeen at the start of the story; Phineas and Ferb are sixteen.

Phineas's breath was hot against her as he kissed her lips, her neck, her shoulders. Their clothes had vanished and his hands were all over her, stroking her sides, caressing her breasts, rubbing between her legs. She pulled him to her, and he was inside her, holding her, stroking within her, so hot against her as her orgasm swept over her like a wave...

Isabella lay back in bed, her breathing slowing as she came down from the orgasm, and turned off her vibrator. Her mother had provided it, along with a birth-control prescription, shortly after she'd started dating Phineas two years ago. "Better to have things dealt with properly before they're needed," Mom had said, despite Isabella turning beet-red several times during that conversation.

She'd been grateful to be able to skip her period due to the prescription, but the vibrator had sat in her drawer, unused, for over a year as she and Phineas had figured out their relationship. So far, they had gone no further than some rather fervent necking. As the two of them got older, however, she found herself drawn more and more to the idea of getting physical with him. With her own seventeenth birthday three months in the past and Phineas's coming up soon, her hormones were making the somewhat terrifying idea seem irresistible. She'd initially taken out the vibrator a few months back to try to take the edge off of them, but now it seemed to be amplifying them instead. Her mother's encouragement didn't help matters - she'd swear her mother actually wanted her to sleep with Phineas, or at least assumed she already had.

I really need to talk to Phineas about this.

She didn't think he'd object. He hadn't seemed averse to touching her - their recent make-out session by her pool had had them both in swimsuits, and she could tell he'd definitely been interested. But the idea of going further was frightening. It felt like a land mine sitting right in the path of their relationship, and she wasn't sure how to get past it.

Phineas was thinking of his girlfriend, Isabella. Her incredible blue eyes which had that special sparkle only for him. Her long, black hair that smelled of lavender. The feel of her body pressed up against his when they kissed, and the way they seemed to fit together perfectly. The incredible sensation of skin against skin when she'd worn that bikini last time they'd made out by her pool, and the feel of the side of her breast as he'd stroked his hand up and down her side...he wandered into imagination from there, of untying her bikini and exploring each other...he gasped as his orgasm hit him, leaning against the wall of the shower.

He opened his eyes and let go of his fading erection, letting the water wash over him as he calmed down again. He'd needed to get that out of the way for the morning; Isabella would be over after breakfast, as usual, and would end up sitting in his lap, as usual. And he was going to get aroused by having his gorgeous girlfriend sitting in his lap, as usual. If he dealt with matters in his morning shower, at least it made it less difficult to restrain himself.

We need to talk about this. I just hope I don't make her run away screaming at the perverse thoughts her boyfriend has about her.

I've been trying to figure out how to talk to her about this for over a month now. Carpe diem, right?

His thoughts were distracted by a pounding on the bathroom door. From the other side, Ferb's voice said, "Hurry it up in there before all the hot water's gone."

Phineas sat against the large tree in the backyard, pondering the day. So many opportunities, so many things to try. He was interrupted by a welcome voice.

"What'cha doin?" Isabella asked.

He looked over at the gate, where he was still stunned every day by what he saw. Isabella was as beautiful now as she'd been cute when they were younger, and that had been cuteness that literally broke the meter. Shapeless pink dresses had given way to fitted blouses, unbuttoned just low enough to show a hint of cleavage, and snug shorts that showed quite a bit of attractive leg. He was continuously amazed that she'd chosen to put up with him for all this time.

"Still thinking," he said. "No ideas yet. Ferb's still eating breakfast."

"Want some company?"

"Always, as long as it's you," he smiled at her.

She came over to him and took up her usual position in his lap, giving him a slow, lingering kiss, her body molding into his like it was made to fit up against him just so. As the kiss ended and they smiled at each other, he tried to figure out how to broach the subject of going further.

His brain blindly groped for the right words, something to convey how much he wanted to do with her, but he couldn't find the magic phrase. He searched for any words to start the conversation, but there was nothing.

The back door opened and Ferb came out. He shook his head and sighed at the two of them curled together under the tree, and came to sit next to them.

I'll try tomorrow, Phineas thought.

I'm going to be alternating days between this and What's Up Doc? until either one of them is complete or I catch up to where I've written at that point.