In Bangkok’s Suan Phlu neighbourhood, teenager Toni has been summoned to help. A group of 10 Taiwanese tourists has swarmed his mother’s business, the Leaf Cannabis Cafe, and Toni, with English learnt at his international school, is patiently trying to talk them down.

“We suggest you try a mid-strength brownie first, not the strongest,” he tells the group who nod their understanding. “And don’t take a half, take a quarter.”