Both are real techniques, but only one of them suits your device, and it is the one the shop told you. Mouth to lung, usually shortened to MTL, is the cigarette-style draw: a slow gentle pull into the mouth, a brief pause, then inhale. Direct to lung, or DTL, is a long open pull taken straight into the lungs like a deep breath, and it needs a much airier device and a much lower nicotine strength to be pleasant. The XLIM family is built for MTL, which is exactly what you want coming off cigarettes. Set up for it properly and it will feel far more familiar: a 1.2ohm pod at 12 to 16W with the airflow slider towards the closed position gives you a tight, warm, cigarette-like draw. That is also why the deep breath attempt is making you cough - you are trying to DTL on a tight MTL setup, and 20mg nic salts taken straight into the lungs will catch anyone's throat. If you ever do want a looser, airier draw, that is what the 0.6ohm pods at 25 to 32W with the slider open are for, and you would drop the nicotine strength at the same time. For now, stay MTL, and be slow and gentle rather than sharp - a vape rewards a longer softer pull than a cigarette does. Our MTL vs DTL guide goes through both styles properly.

The slow gentle pull is the bit that takes longest to unlearn. I was drawing on it hard like a roll-up for my first month and wondering why it was harsh. Ease off and it gets much better.

Closing the airflow down was what made mine finally feel like a cigarette. Wide open it feels like breathing warm air and you never feel satisfied by it.

Stuck with the mouth first method, closed the airflow off a bit and slowed right down. Completely different experience, no coughing and I am not thinking about cigarettes half as much. Appreciate the patience with a basic question.