noun
area around the navel; treasure trail; sagittal hair
Refers to the region surrounding the navel, often in the context of body hair (the line of hair from the navel downward). 'Treasure trail' and 'sagittal hair' are specific to the hair pattern.
彼はへそまわりの毛を気にしている。
He is self-conscious about the hair around his navel.
水着を着るとき、へそまわりが気になる。
When wearing a swimsuit, I worry about my treasure trail.