I love to say Raxicoricofallipitorious given half a chance. Just a quick note about me. And now, back to your regularly scheduled program.
The Doctor quickly scanned Sherlock and John with his sonic screwdriver. "Amazing! Your bodies have been totally transformed into that of a 3-year-olds!"
"Yeah, we can see that, Doctor! But how?"
At John's question, the Doctor turned sheepish. "Well, I was a little busy while I was leaving the TARDIS, and instead of taking the bottle of intergalactic apple juice made on Raxicoricofallipitorious, (which is amazing by the way,) I may have taken the de-aging serum from here in the 23rd century. Not to worry, there is a cure…I think." He barely mumbled the last bit, but Mycroft still heard it, and immediately lost all the composure he had scrounged up. "You think. You THINK?! Listen, I don't know just WHO you think you are, but nobody hurts my little brother and gets away with it! Who ARE you?! Talking about made up planets and the future like you're some…some…time traveling alien or—" he stopped short. It wasn't like he hadn't heard the rumors, but the man who was whispered about in the darkest corners…the Doctor…that was what this man was called too… "But you're not-I mean, you can't actually-You're just supposed to be a rumor!"
"And yet here I am! Hello, I'm the Doctor! And you must be…Mycroft Holmes! I've heard of you!" He did a quick once over of Mycroft. "You're not as fat as they say. They're a bit rude then, but people tend to be…" Sherlock laughed and John smiled as Mycroft's ears turned red.
"Wait! No! Yes! No! Sorry, got a bit distracted there. Sherlock, John, can you come over here? I want a good look at you." Both boys trudged slowly over. All they were wearing were their shirts, bunched up and dragging where they met the ground. Neither had any immediate problems, and all wits were with their respective owners, though Sherlock kept absentmindedly start to suck his fist then catch himself. "May as well keep it in your mouth, brother dear. It's not as if we'll hold it against you." Mycroft teased as he eased himself onto the couch. This was met with a stern, "Shut up, Mycwoft." And a personal scowl from Sherlock to Sherlock about his adorable inability to say his "R"'s. John laughed a little. "Oh, like you wewe the pewfect thwee-yeaw-old, then." Sherlock snapped.
"No, sorry, Sherrock, it's just a bit funny. In fact, it took me ages to wearn my—" he stopped and kicked himself.
"Youw L's?" Sherlock supplied with a smirk.
"Fist sucker."
"Suck-up."
"Behave, you two."
"Shut up, Mycwoft." At John's smirk, Sherlock tackled him, then pounded him hard between the shoulder blades. It took both the Doctor and Mycroft's combined strength to rip the two away from each other. At which time both boys decided it would be perfect to continue their nap where they left off, Sherlock curled in Mycroft's arms, John clinging to the Doctor's suspenders in one hand, his bow tie in the other. The Doctor quickly changed his assessment of the situation. "Okay, so the only thing that really survived this transformation was their memories. Otherwise, they're 3."
Mycroft added, "And as if that weren't bad enough, it seems Sherlock has just found himself a new punching bag."
All the Doctor could find to say to that remark was, "Well this is just lovely."