Is it possible for masturbation to shrink your ?

A few years back I measured myself at about 6". The other day I was curious so I got myself hard and measured again. This time I came out to 4". Slightly worried, I Googled the question and came up with several conflicting answers. Most of the links I hit said it was not possible. A few said that too much masturbation can make the smaller. However, these sites also marketed and sold those stupid "male enhancement" drugs so I'm a bit reluctant to believe them. So I'm posting this question to a community in hopes I can get an honest answer from someone who might actually know. Thanks in advance.