"Slowburn" is a fanfic term that refers primarily to pacing. The fics are, in a word, slow - they take their time, there's often a lot of exposition, and exploration of character's motivations, emotions, and development. The term is also used almost exclusively to talk about romances - those are romances that take their time and let you experience each moment as it happens.

And, of course, they're Johnlocks - John Watson and Sherlock Holmes' romantic pairing - so this week you're going to watch John and Sherlock fall in love, revealed slowly, step by step, each emotional development explored in turn.

Happy 'Shipping!!