Created by a midwife called Nobuko Watanabe, otonamaki is designed to recreate that snuggly feeling babies get when they’re swaddled, which in turn emulates the protection and comfort of the womb.
The treatment involves lying on top of a large piece of breathable cloth and hugging the legs in towards the body (think Happy Baby pose in yoga). The attendant then wraps and fastens the cloth so you’re nice and secure, and rocks you gently for 20 minutes.
Frankly, it looks creepy and sounds claustrophobic (the cloth is tied over your entire body including your head, so you’re completely encased), but proponents claim otonamaki is incredibly relaxing and can help with flexibility. The rocking and rolling is also a form of self-massage — increasing blood flow and soothing stiff, knotted muscles.
However, some doctors advise against it. Visvanathan Ravi, Senior Physiotherapist at Hallmark Physiotherapy, told the BBC he is wary of otonamaki’s long term effects: “I totally disagree with the treatment method. If a person stays in the position for 30 minutes, I’m sure there will be spine problems. It’s not advisable to do this treatment.”