Mouth to Lung Hit. Mouth Inhale, Mouth Inhalation, or MLT. We’ll use MLT throughout the rest of the guide.Direct Lung Inhalation. It includes Lung Inhale, Lung Vaping, Lung Inhalation, Direct Lung Hit, Lung Hit, Direct to Lung Hit. Additionally, it also includes Direct Lung Inhalation, Lung Vaping, or DLI. We’ll use DLI throughout the rest of the guide.