Sherlock had been awake for a while now. He never needed as much sleep as most people. But he had stayed still and kept his breathing even and waited for John to wake.

When he felt John stirring, he worked to stay still and breathing steadily, listening to John as he moved around and snuggled up close. It was hard not to catch his breath, but he manages it, staying "asleep" until John settled back down again. It wasn't long until John was back asleep, and Sherlock, surprisingly, falls back to sleep with him.