Water pumping and air pumping expansion will only last until the expansion diminishes and you return to your normal size. The thing that needs to be taken to heart and much faith should be put in is
SRT and it's approach to this. In Penis Enlargement temporary gains are important because they eventually become permanent and for many years this is how Penis Enlargement operated.
SRT changed this in many ways but most specifically on this topic,
SRT demands that expansion and elongation be held as long as possible for the fact that IF the expansion/elongation is held through the healing time (after training until the next routine) you will make gains much faster....MUCH FASTER.
SRT explores and explains all of these things and more...please read through if you have not yet.