Boston Opener Share definition Flag to say a rude comment to a girl from boston so she gasps and opens her mouth while you proceed to stick something in it. mark- "girl your so fat" Sherry- "gasp" =o mark- " the Boston Opener.... works every time" Boston Opener by dolly311 August 29, 2010 0 0 Get merch Get the Boston Opener mug. Buy Now — $32.95 See more merch