Sherlock lay, as usual, face-up, hands folded under his chin on the couch. John would be home in approximately five minutes and a half, plenty of time to think his plans through. He had not met John this morning, John had been gone to work before Sherlock could approach him. He had been up all night, not a rare occurrence, but had been so lost in thought for an hour or two that he had only heard John leave. Then it was too late of course.
Yesterday, John had said that if he wanted to win someone's heart, he had to try courting. So Sherlock had spent the whole night and morning on how one would 'court' the other. He had filled his brain with contemporary files of 'wooing ladies', 'hitting on someone' and 'courting'. They were all different approaches to luring someone into dating/flattering someone, sparking physical attraction and the like. The rest of the day, Sherlock had thought of a plan, which he now was going to put into action.
Regarding on John's light footsteps on the stairs, he was in a giddy mood. Perfect. When John came in, Sherlock asked without giving John the opportunity to even greet him:
"John, would you like to go out for a drink?"