18 of the dosing mechanism to insure that the diaphragm 102 seals to the piercing nozzle 105 in the contact area 116 and that the membrane 103 is stretched away from the fissure point to minimize flap formation and interference in sealing area 21 in order to achieve the desired spray pattern 114 an embodiment of a piercing device 800 is shown in fig8 in which the piercing tip 810 is formed as a projection or nipple concentric with the delivery opening 818 in the elongated oval shaped body 812 of the piercer also shown in this view is the base 814 and the entry port 816 the nipple is designed and sized to be the first contact point with the film and to stretch the film to create a non contact region between the initial contact point and the shoulder region 820 or edge of the body this interaction is shown in more detail in fig1 fig9 is a side view of the piercing device as in fig8 showing the long axis of the oval shaped body and can be compared to fig1 which is rotated 90 u00b0 from the perspective in fig9 to show the short axis of the oval shaped body fig1 is a cross sectional view of a piercer as in fig8 showing an example of a fluid path 910 through the base 814 of the piercing device it is understood that although a single entry port is shown a device can include one or more entry ports spaced around the base of the device fig1 is a magnified view of an oval shaped piercer body 200 with a nipple shaped tip 202 at the point of first fissure in piercing a film 204 as shown in the drawing the film 204 is stretched.