Y for Yoga
The Downward Dog was a position where you were on all fours, the upper part of your body crouching down and the lower part sticking straight up.
John had only recently started yoga. He was careful not to stretch his war wound too much.
He didn't know that someone was looking at how his buttocks were raised. Sherlock was enjoying the view.
Before John noticed Sherlock behind him, he felt a tiny slap. It didn't hurt but he was flabbergasted.
John swiveled his entire body so that he was sitting down facing a smirking Sherlock.
"What was that?" he asked.
"It was fun," Sherlock answered.