Now, remember, if there is a vaccuum in there, the pressure difference will cause for a positive seal with the lips.
Just sayin’.
86 posted on 07/10/2015 7:18:06 AM PDT by Lazamataz
(NoNOnoNoNoNOnoNoNoNOnoNoNoNOnoNoNoNOnoNoNoNOnoNoNoNOnoNoNoNOnoNoNoNOnoNoNoNOnoNoNoNOnoNoNoNOnoNoNoNO)