"My. My. Myyyyyyyyy."
Mycroft opened his eyes in the middle of the night. "What?"
"Come play. Now." For a six-year-old, he had a most irritating method of getting what he wanted—attention.
"Why?"
"Because I'm wide awake and if I don't play then I won't fall asleep again and then I won't be happy tomorrow and I'll be cranky and steal your books and then you'll get upset and tell mother and then I'll have to sit in a corner and that'll make me more cranky."
Mycroft rolled over and checked his clock. 3:01 am. "Fine."
It wasn't long before Mycroft discovered why his little brother was overly hyperactive, even for him. There was chocolate icing all over his face and hands and an enormous slice missing from their parents' anniversary cake.
"Sherlock, did you eat mummy and daddy's cake?"
"Nope." The lie came quickly.
"Then where did it go? Last night, there was over half the cake left and now there's less than a third."
"Um…it was the gumwoolies!" Sherlock's favourite imaginary scapegoats. "Yeah, I saw one. And it was big and blue and furry and had one eyeball in the middle of its head and it was eating the cake so I came after it with my sword" (he brandished his cardboard pirate sword) "and then I tried to fight it off but it scooped up a bigger bite and ate it right in front of me! The cheek! So I poked it and told it to leave their cake alone or I'd hunt him down across the seven seas and run him through with my cutlass!" Sherlock spun as he talked, and fell down, dizzy, and let out a small giggle.
"Then how, precisely, did you get chocolate on your face?" Mycroft crossed his arms. It had been a very special cake, a one-of-a-kind cake made with only the purest of ingredients, made by a family friend and even then, still very expensive.
"It's not chocolate! It's…" Sherlock closed one eye and tilted his head. "Gumwooly blood! Yeah because it still kept eating the cake so I chased after it and then I sliced it with my sword and and and it exploded all over me and I haven't cleaned it up yet."
Mycroft sighed. All he had to do was wait for Sherlock to tire out. "And how long ago was this?"
"…fifteen minutes."
"Ah. In that case, yes, I will play with you." But what he did mostly was watch as Sherlock bounded all over the furniture, burning through the exceedingly large slice of cake, playing everything from The Floor is Lava to statues as he ran around.
At 4:47, Mycroft turned around in the middle of statues to find Sherlock fast asleep on the sofa, the sugar crash having knocked him clean out, and a little spot of drool forming.
"Come on, brother," Mycroft said, lifting Sherlock into his arms. The littlest Holmes's hands closed around Mycroft's shirt and he sleepily mumbled something indistinguishable. Mycroft lowered his brother into bed and tucked him in, wiping the icing from his face with a slightly damp napkin.