Touching up and relighting may seem to be completely synonymous but they’re not exactly the same thing. “Touching up” a cigar generally refers to very selective lighting of a particular section of a cigar. You’ll generally want to touch up your cigar when one side begins to burn more quickly than another which leads to crooked burns. This may seem inconsequential at first but if you let it keep burning crookedly the cigar’s integrity will eventually be compromised and it’ll likely ash all over you. That’s a situation every smoker wants to avoid.
Crooked burning occurs most commonly with lower tier cigars but even more expensive and higher quality sticks will occasionally smoke in a lopsided fashion. If you notice your cigar’s burn line begin to angle awkwardly you can first try and lightly (very lightly) grind off the offending ash so that it burns more evenly. Try placing the unburned side face-down in your ash tray; this will help keep the oxygen in and retain a more even burn line. If these practices don’t work, then it’s time to turn to you lighter of choice. If you’re using a butane burner turn it down low and gently burn up the non-burned side, moving in quick, rapid successions to keep from “overcooking.”
But what to do if you’ve set your cigar down for a extended period of time and return to find it completely burned out. There are two useful ways to get your stick burning again with maximal flavor. For the first take your cigar cutter and snap off the entire burned portion such that only unburnt tobacco is showing then apply your lighter. For the second method knock out the ash and use either your fingers or a small utensil (such as a matchstick) to clean out all the leftovers until there’s nothing but hardened char showing then lightly skim the surface with your lighter and blow gently on it until re-ignition.