Embodiments of the invention provide methods and devices for improved drainage systems and tubing. In one embodiment, a context-sensitive flow interrupter is provided that inhibits or facilitates flow of fluid when engaged with a mating holder. In another embodiment, outflow is optimized through control of the pressure in gas pockets in a tube, drainage tube or assembly. In one such embodiment, gas pockets are vented to inhibit excessive back-pressure or suction on an organ, vessel or cavity being drained. In another such embodiment, loops in the tubes are avoided by using a mechanical template in the form of a groove or peg assembly to thread the slack in the drainage tube to generate a monotonic gradient. In another embodiment, such as for active drainage systems, a bypass channel is provided that allows an applied vacuum to go around an obstruction created by the collection of fluid in an undrained dependent loop.