They're in their early teens in this one, not quite 16, maybe preteens or something.

"Come on Don, you've been reading about this for an hour! Let it go."

At Mike's exasperated voice Don did glance up from his notes, but he only looked mildly irritated at the interruption. "You should be listening to this Mikey, do you realize that we live below a species that is more closely related to us then what we naturally are?"

Not much of this seemed to get through to him, but at least he had stopped complaining, so he went on talking mostly to himself, "the human female reproductive system is a series of organs primarily located inside of the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vagina…"

"Oh shell please stop, I'm begging here!"

Again Don had to look up and glare at his irritating little brother at the interruption.

"What? I was reading much quieter that time, if you don't like it then you can ignore me."

Mikey's blue eyes swiveled from his game to his brother with a look of disgust on his face as he answered, "hello, you can't go saying words like that and just expect other people to ignore them."

Donnie tilted his head to the side as he reread his notes again, then asked, "what word in particular are you talking about?"

This time he actually paused his game and got on his knees to turn around and look at his bro as he answered, "the V word, you can not go saying something like that in public dude, better yet just not at all."

"Er, the V word?" Don asked now trying to hide the smile on his face, "and what word is that exactly?"

Mikey narrowed his eyes and snapped, "come on, you're the genius of the family, figure it out."

Now thoroughly trying to hide the grin on his face he started, "oh you mean the word vagi-" and like the two year old he so pretends he was Mikey slapped his hands over his ears and started singing at the top of his voice, "LALALALALA!"

Don would have told him to shut up if he wasn't laughing so hard, he brought new meaning to the anagram rolling on the floor laughing.

Attracted to the living room by all the noise Raph and Leo came out of the kitchen and glanced around at the odd sight.

They were all used to seeing each other fighting, though with Mikey and Don it was rare, and were also used to listening in to the odd conversations and following laughter, but this wasn't something they saw much.

"Do we even want to know?" Leo asked a bit louder then normal to try and make himself heard.

Amazingly Mikey did hear his older brother through all the noise and he paused for a moment to remove his hands from his ears and answer, "Leo, Don's being bad. He needs to go do flips for saying bad words."

"Oh, and what words are those?" Raph asked still watching his purple banded brother gasping for breath on the floor.

"NO! Don't-" Mikey protested and he actually started waving his arms around like he could stop the words before they left his brothers mouth.

This didn't stop Don from sitting up right and rubbing the moisture from his eyes then responding, "I was looking up some stuff about the human systems and Mikey didn't approve of some of the words Wiki was using."

Mikey glared at his brother over at the computer and defended himself, "there are some words that people just shouldn't say. What you said is one of them."

Leo wasn't one to give up on anything, but even he decided that this conversation was going nowhere fast so he headed up to his room to try and get some peace and quite, a lost cause in this place.

Raph however was too entertained by this and wanted to see how far he could push this. "So your saying that certain words shouldn't be said and vagina is one of them?"

Mikey shuddered but nodded, then a wary look crept onto his face at the evil look on his red masked brother.

Raph kept going in a would be casual voice, "so what are some other words that shouldn't be said? What about boobs huh? Can we say that?"

His baby blue eyes widened in fear as he realized what his brother was doing and he opened his mouth, but before he could get anything out Donatello interrupted, "what about ovaries or testicular? Can we say either of those?"

Mikey gave up on trying to stop his brothers, and instead grabbed a pillow and slammed it over his face humming under his breath to try and block out the noises of those around him.

The two others raised their voices as they carried on, still trying to get a reaction from the youngest, "or how about period and once a month or even cycle?"

All three boys shuddered at that, suddenly glad that they had no female contact for this dreaded reason.

A truly evil looked passed through Don's face as he walked over to the couch and half yelled, "well I know one word that shouldn't be used, orga-"

Mikey wailed and fell of the couch in his attempt to escape his brothers.

Ringing laughter could be heard throughout the whole sewer system, and one high pitched voice screaming, "Don't say that!"

Hahaha I don't think you really want to know where I got this conversation from, just review anyways and tell me what you think.