This video shows how to use a hair dryer to mould a Totobobo mask.
The heat treatment can be apply to any parts of the mask, for example, the nose and chin area. The possibilities are limitless. You may need to try moulding the mask several time to achieve the best fit.
This "moulding" feature helps to improve the overall face seal (protection) and wearing comfort.
Alternatively you can use hot water to perform the ReShape, follow the link here: youtube.com/watch?v=p9vl-_RPUcs