Disclaimer: I own nothing, and only borrowed these characters for a little while.

The World's Only Consulting Detective watched the scene from the corner of his eye.

An overtired toddler was being soothed by her father. Whilst this behaviour was one he had seen before, he had never paid it any great attention before.

Rosie's head rested on John's chest. Eyes shuttered close as her father ran a gentle hand through her hair. Equal pressure applied constantly throughout. Cries petered out. Even breathing. Outcome: slumber, seemingly due to soothing effect of motion and closeness.

Deduction: further experimentation required.

Later that night, Rosie abed, he abruptly rose from his seat and marched to the sofa where John sat, seating himself heavily.

"What are you doing Sherlock?" asked John mildly at the invasion of his personal space, looking up from his reading.

"An experiment."

John watched with amusement as Sherlock rearranged his long limbs into the tight shared space, plonking his head on the doctor's chest. When he failed to move and offered no further explanation, John rolled his eyes and picked up his journal once again.

Several minutes passed before a voice shattered the silence.

"Put your hand in my hair like you do with Rosie."

John blinked. "Okayyy."

Gingerly slipping his fingers into the soft hair, he slowly carded them through his curls. He felt the body of the detective instantly melt against him.

"It is a most effective method of calming down oneself," Sherlock remarked before shutting his eyes.

John didn't bother responding as he picked up his paper once again.

Apparently this was going to be normal now.

Next Chapter: ...