AC DC’s “Big Balls” isn’t about it per se but does allude to it at one point.
“Touch Myself,” I think, by T-Boz (of TLC) & Richie Rich.
“I can feel it coming in the air tonight” by Phil Collins ?
‘Get a Grip’ by Semisonic.
“Icicle” by Tori Amos
“One More Minute” by Weird Al Yankovic (it’s not all about masturbation, but it does contain the line:
“I’m stranded all alone at the Gas Station of Love
And I have to use the self-service pumps…” 
“She Bop” by Cyndi Lauper
“Blister in the Sun” - The Violent Femmes
Here’s a whole list!
“Playmate of the Year” by Zebrahead.
Springsteen’s *Blinded By The Light * - Don’t have the exact line handy, but “as the adolescent boy pumps his way into his hat”
“God Bless the USA”?! 
Sodomy from Hair
Paulina* by No Doubt.
Sounds painful. Do you have to freeze the hair first? Otherwise, it…
…what?
…oh…
Never mind. 
:smack:
In my defense, I suppose that after a while it could make you a basket case.
Just before you go blind.
“Firing the Surgeon General,” complete with MP3.
Rodney Carrington’s Dear Penis
Imaginary Lover by Atlanta Rhythm Section.
“He’s My Best Friend” – Jellyfish
“Pink Thing” – XTC. Yep, this one’s a double entendre, about both Andy P’s penis and his baby boy.