I just don't get how this can be true. Don't people have different sizes mouths? How can if fit going in but not coming out? Am I just falling for a stupid joke? Either way I kinda want to try this now.
I don't know if this is true, but it seems plausible that the bulb could have asymmetric strength depending on the angle force is applied. Glass does weird things! Case in point: Prince Rupert's drops.