A container comprising a first layer of sheet material defining a compartment for holding a fluid material, first and second peripheral edges defining lateral boundaries of the compartment, a first end defining an opening end and a channel having a first cross sectional diameter extending into the compartment between the peripheral edges, a second end defining a bottom of the compartment, a valve comprising a first layer of flexible material of higher stiffness than the sheet material on a first side of the channel, a valve positioned on a second side of the channel, where the first layer and the valve are joined on opposite sides of the channel via attachment means restricting the first cross sectional diameter of the channel where a deflection of the flexible material in a direction substantially perpendicular to the longitudinal axis provides increased resistance to deflection in the direction along the longitudinal axis.