Never Pour For Yourself (手酌の禁止 - Tejiaku)
The custom of avoiding pouring bottled alcohol (beer or sake) for yourself ('Tejiaku') when drinking in a group. Instead, you wait for others to pour for you, and proactively pour for them, building strong social bonds.
An expression of mutual care and 'Nominication' (drinking + communication). Self-pouring implies you are drinking alone or lack friends to look after you. Pouring for others shows your attentiveness and respect.
When your companion's glass runs low, pick up the bottle with both hands and pour for them. When your own glass is empty, wait patiently for someone to notice and offer a refill. Always hold your glass with both hands when receiving a pour.
What is the custom of 'Tejiaku' that you should absolutely avoid during group drinking in Japan?