A valve assembly includes a valve collar (14), a rotatable valve control member(16), and a flexible valve member (20) disposed therebetween. The valve controlmember and the valve collar are aligned to define an elongated passageway, andthe flexible valve member is disposed along the passageway. The valve collaris structured such that at least a portion -thereof (41) is capable of radial flexureupon engagement with a mechanism (51) on the rotatable valve control member.One end of the valve member (62) is secured to the valve collar, and the other end(64) is secured to the rotatable valve control member. Upon rotation of the rotatablevalve control member relative to the valve collar, the mechanism of the rotatablevalve control member engages the valve collar portion in a manner such that thevalve collar portion flexes in a radial direction and a tactile sensation is producedthereby, and the flexible valve member constricts from an open position to a positionwherein the flexible valve member opening is at least partially closed to passageof fluid therethrough.
