"enamelling" means: The process of applying enamel to a surface — in metalwork, ceramics, or decorative art. A layer of vitreous glass-based coating is fused to.... There is a drug-related reference, so this is one worth noticing without overreacting. Many teens encounter such vocabulary through music, film and friends without any direct involvement. A neutral, curious conversation about where they heard the term and what they understand by it is far more useful than a confrontation. Watch for repeated context, not a single word.