I would agree with Big Al ^^^^^^, and also I'd like to clarify this a bit :
It's probably just semantics, but in my mind there's no "active" vs "passive" stretch in this context.
The penis is basically smooth muscle and vascular tissue. It cannot be active or passive (contract and relax) in the way skeletal muscle can. The benefits of active stretching in the technical sense only apply to skeletal muscle. Active stretching includes techniques like Proprioceptive Neuromuscular Facilitation (PNF) and reciprocal inhibition, etc. They actively engage proprioceptors within the muscle fibers and points of origin and insertion and generally lead to dialing down the stretch reflex, which allows for access to greater range of motion. This is in contrast to passive stretching, which is basically just pulling on a muscle in the hopes it will lengthen, which typically doesn't work very well with skeletal muscle.
Now, the penis is different because it's mostly smooth muscle, so it can't contract or relax "on it's own". In a sense it is always passive. Even when manually stretching, the force is being applied externally by the hand/arm/etc. I fail to see why this would be more "active" than force being applied by an extender or some other device.
This is an interesting read -
Mechanically Activated Stretch Reflex Exercises - about penis stretching. Notice the use of "mechanically activated" to modify "stretch reflex". Again, I see no difference between the mechanical (read, external) activation via an extender vs an okay grip.
All that said, I have never used a phallosan or any other device besides a clamp. I've gained almost 2" BPEL in a little over 6 months using only manual stretching, jelqing, squeezing, and edging. I know that stuff works. I just don't really buy the active/passive distinction.
The big advantage of manual work is probably more related to
stress-strain theory and bio-feedback. Basically, the penis is elastic tissue. Cyclical stretching or as Big Al said, shorter bursts of stretching, is more effective for lengthening than extended periods of strain (think about a rubber band here). Also, using your own hands is superior because you get immediate feedback as to how far is too far and when to stop or change angles, etc.