I can honestly say, I have NEVER heard of masterbating lowering ones IQ. I am in my 40s and have masterbated since I was 12 or 13. I have resorted to masterbation when it has been "that time of month" for my lover.
Before I got married, and was dating alot, I found myself masterbating quite a bit, mainly when the girl I went out with was a big tease.

Any way, what I'm getting at is, masterbation feels good and as far as I know, it has never hurt anyone