That was a strange offer, but in that moment it was strangely perfect. Possibly they were the only two men in history for whom outwitting was an alluring prospect. Holmes was impossible, aggravating, egotistical -- and yet he loved and treasured all of him. Watson gave a low chuckle, momentarily dropping his gaze down to relish the sight of his hands curled around Holmes's sides, then lifting his eyes again.

"I feel like I ought to have more information on the nature of this 'outwitting' before I agree. Very well," he murmured, "if you must." Despite his words, his tone was inviting, amused, affectionate.