Days have passed since Doof and Perry's confession towards each other and the two couldn't be happier. There were some occasions where it was extremely awkward for the platypuses since they were still getting used to it but it was always made up with lots and lots of bill nudging. All in all it was heartwarming for their owners to watch.

"Hey Doofy! The day to remove your tail cast is almost near! Soon you can move your tail around freely without having to feel any pain, aren't you excited?" Phineas enthusiastically asked the purple platypus.

He's response was an answer in the form of chattering but Phineas knew exactly what it meant. 'You bet I am!'

"Great! You just keep resting your tail, if any of you need us Ferb and I will be outside!" With that said the red and green head ran out the doors, covered in layers of warm clothes, scarfs and shining smiles.

"Your boys are really cheerful." Doof started when he was sure they were alone. "I get a new cavity every day I see them."

Perry smiled at the others saying. "You get used to it after a while, your teeth grow an extra layer of child glee protection."

The ex-human laughed, deciding to leave it at that he inched closer to the teal platypus and cuddled his side, accidently bumping him with his shoulder. Perry, taking it as a playful start, bumped him back a tad harder, and this is how the platypuses found themselves starring in an intense game of nudge and shove that led to entangle limbs all over the place. Once they managed to separate Perry leaped to Doof, trying to pin him down as the scientist turned and evaded as much of the moves as he could, laughing out loud as he ran, zigzagging left and right circling around the living room. Doof made a wrong turn and ended up cornered with no way to turn, but before he could direct himself back he felt a sudden force clamp down on his still sensitive tail.

Yelping, he turned to the source and found Perry had not only bitten down on the only exposed part of his tail outside the cast and still clamped on but was also gazing at the appendage with deep interest.

"P-Perry? Ow! What are you doing? Let go! My tail still hurts!"

That must have done the trick because Perry blinked himself off whatever trance he had been in. Perry looked up at him and found his eyes widening, letting go of his tail and backing away as if it burned.

Twisting his body to softly message the bitten area Doof asked. "What was that about? Why did you bit me?"

He saw Perry was twirling his fingers together sheepishly and looked as if he was blushing. "I-I don't know what came over me, I didn't mean to bite you."

"Yeah well, oww it still hurts you know." He indicated, still messaging his tail.

"I'll go get something for the pain!" Perry quickly said, running off in a direction.

Doof looked at the spot the platypus disappeared from and gazed off in confusion. What in the world?

After keeping true to his word and bringing a red liquid substance that not only dulled the pain but also made him slightly drowsy both platypuses sat distant from each other. The incident with the tail biting left Perry feeling extremely awkward for reasons Doof couldn't fathom, none the less he respected the teal platypus' space and didn't press the matter. Even though he really, really wanted too.

Sometime close to the boys bed time Doof tried to lighten up the mood. When Perry least expected it he stalked his way closer, lifting his tail to prevent the cast from making contact with the carpet and making any sort of noise, with his tail still recovering the action was a lot more painful than it looked.

When he was within pouncing distance Doof gave the teal platypus' tail a look and changed tactics. As quick as his Ocelot parents taught him he targeted his prey and made his move, biting down on Perry's tail.

Perry, who was startled at the sudden action, stood on his hind legs by accident and quickly turned towards Doof. "Heinz! What are you doing!?" He scolded.

Releasing the tail from his hold, Doof grinned up at him. "Giving you a taste of your own medicinnee! How do you like having your tail bitten huh?"

Still staring up at the platypus Doof's grinned started to subside. Perry wasn't smiling, but neither was he mad. The teal platypus had crouched down and was now sitting, face facing downward, his eyes glaring through the ground.

Even with the fur in the way Doof can tell he was blushing furiously.

What?

"Doof, don't ever bite my tail again." Perry started, switching back to the acquaintance name, his voice sounding deep and downright serious. "I won't be held responsible for my actions if you do, so don't ever, ever, bite my tail again."

With that said he turned away from Doof and walked to Ferbs bed, jumping up and cuddling next to him.

Doof was left alone standing in the hall. He ended up sleeping by himself on the pet bed in the living room.

What just happened?

Everyone always said that the next day after an argument would be better, it wasn't.

Perry didn't just keep his distance that morning; he was flat out avoiding him!

There was no 'good morning', no 'how was your lonely night?', and definitely no 'the reason I'm avoiding you today.'

And it all started because Perry bit his tail! It's not like it was Heinz's fault!

Then it hit him, it started because of tail biting! Perry is avoiding him because he bit his tail!

The wheels were turning inside the ex-humans head. Tail biting, did it have some sort of significance? Maybe in platypus term it meant something bad?

Heinz jumped; did he just insult Perry by doing that? No, that can't be right. Perry bit him first he should be the one upset, not the other way around, the platypus has no right to be angry at him when he started it! Then what else does it mean?

The purple platypus growled as much as platypus voice strings would let him. This isn't going to get him anywhere, he should have studied on the subject of platypuses more!

That's it!

Quickly finding his legs Doof ran up the stairs and after checking for any signs of the other platypus entered the boys' room. He turned on the computer and started the search engine for 'Platypus Tail Biting.'

The first site that popped out left him mouth opened and shocked.

Monotreme Reproductive Physiology and Behavior?

What in the?

Shyly clicking on the sight he ended up reading a full introduction on the Platypus species and background, quickly skipping through reproduction and egg and embryo development and reading halfway through mating behavior, making him more nauseated than he already is. He abruptly stopped when certain entail involving tail biting came up.

'Pre-mating behavior generally includes increased bodily contact, following and circling, and the male biting the female's tail.'

What. In. The. Teufel?

Male? Biting the female's? Tail?

Doof read and re-read the sentence over, and over. Losing count on how many times he did.

Perry bit his tail, male platypuses bite female platypus's tail, Perry bit him first.

Doof is the GIRL!?

He mentally screamed in his mind.

There is no way he is the girl!

There is no way Doof is going to be labeled as the girl!

There is no way Doof is going to let Perry be labeled as the boy without a fight!

This means dominance!