Never
They wandered aimlessly through the corridors, shoes noiseless on the stone floors, never speaking, never even looking at each other. No teacher disturbed them; no caretaker's cat stalked them.
The sunlight spilled, ignored, through the high windows. The other students avoided them, but not without reason.
They never talked, never touched, never glanced sideways. They never laughed together, never cried together, and even tried to keep their breathing out of sync.
They only walked together. It was their common ground, their form of release. Afterwards, they would part without a word, never looking back.
Then one day it all changed. One turned to the other and kissed his companion.
"That was… Different," his companion said, minutes later, flushed.
"That was… How I feel," he replied.
"It's different," his companion said. "But, sometimes, different is good."
Those were the last words Harry said before he leaned in to kiss Draco again. That was a defining moment in their now-shared lives, and, from then on, neither of them looked back.