At the beginning of Season 4 Finch advised Reese that he should get a hobby, he just had never expected this...

There had been a time, once, when Bear had not been called Bear.

"His attraction to Harold had come as a surprise, but by no means an unpleasant one. After all the dark, soul-numbing years with the Agency it was a wonder he was still capable of feeling affection at all, and he'd indulged shamelessly in the intoxicating buzz of his new infatuation..." The quest to save a famous anthropologist becomes a very personal mission.

John's never been ashamed of his scars-they're a record of his history, and he earned every one of them. Harold, he knows, has never felt anything but. So John teaches him otherwise. In the best way he knows. The sex way. Reese/Finch.