Flexible filament that can be used with a bowden extruder?

I need a certain, rather complex shaped, flexible rubber gasket for a Dyson vacuum cleaner. Cutting it by hand would be a pain in the rear. My idea is to 3D-print it on my Ender. And now for my questions. a) Is it a myth, that you cannot use flexible filament I a bowden extruder? b) If no, does anyone of you guys can propose a...