"Can I help you, Sherlock?"
"Mmmmn." Long fingers pulled and carded through John's hair, blunt nails lightly raking across his scalp. "You're using new shampoo, John."
"Only because you used up all of mine." Closing his eyes, he tilted his head forward a little. Sherlock promptly nuzzled into the short hair at the nape of his neck, breathing deeply through his nose.
"Verbena... Lavender... And pomegranates? John, are you using women's shampoo?"
He chuckled under his breath, reaching up to tilt the screen of his laptop shut. "You don't like it?"
"You're putting words in my mouth again, John. To say that I don't like the smell when I'm so clearly demonstrating my enjoyment is preposterous." He inhaled the smell of the shampoo again, raking his fingers through the only-slightly-longer-than-military-standards-and-still-damp-from-the-shower hair on the top of John's head. "To have you smelling of something other than sulfates and tea tree oil is hardly unpleasant. In fact, I would encourage you to use this shampoo more often."
"Only if you promise not to use it all up on me again."
"I think the smell of sulfates and tea tree oil suits me much better than it does you, John."
"Does that mean I'll have to buy my old shampoo anyway?"
Sherlock nuzzled deeper into the short hair at the nape of his neck. "Yes, John. It does."