A flexible container formed of flexible web material is provided. The container includes four panels forming: a body portion; a neck portion; a flare portion extending from the neck portion; and a tapered transition portion between the body and neck portions; wherein the neck portion has a reduced width and the flare portion has an expanded end. Also disclosed is a method of forming the aforementioned container comprising steps of: biasing the expanded end to define a circumference; moving, via a mandrel comprising a groove, the fitment within the circumference and through the expanded end to a first position in the neck; transversely cutting away the expanded end by advancing preferably v-shaped blades through the neck and into the groove preferably without rotation of the mandrel, container, or blades; moving the fitment to a second position in the neck; and sealing the neck to the fitment.