A dab is a small amount of cannabis concentrate that is vaporized by placing it on a heated surface and inhaling the vapor. "Dabbing" is the act of doing it. Concentrates like badder, sugar, shatter, live resin, rosin and diamonds are commonly dabbed.
The traditional setup is a dab rig, a water pipe built for concentrates, with a "nail" or "banger" (usually quartz) that is heated with a torch. After heating, you wait for it to cool slightly, place the dab on it with a dab tool, and inhale. Electronic rigs (e-rigs) and concentrate pens heat the surface electrically with set temperatures, which is simpler and more consistent.
Dabs are strong because concentrates often test above 60-70% THC. A small dab, about the size of a grain of rice, is plenty to start. Take it slow and wait before having another.
Temperature matters. Too hot can taste harsh and burn off flavor; lower temperatures give better taste and a smoother hit.
Safety tips: use torches carefully, let equipment cool before touching, keep everything away from children and pets, and never drive after dabbing.