Image from Someecard.com. Used without permission though I doubt they care.
I'd like to tell you that Rush Limbaugh is alone in his theory that his dick is small because of feminism. But alas, no.
What's funny of course, beside the blunt truth that, no, feminism doesn't make your penis smaller (though maybe your conservative neighbor's industrial effluents might be) there's the even more fundamental man-hating anti-feminist idea that penis size is the only element of sexual attractiveness in men.
Quick aside: The author Mary Roach excels at highlighting tragic/comedic aspects of the human condition. In her excellent, readable book Bonk, the Curious Coupling of Science and Sex, she mentions that, evidently, men with larger-than-average penises are at least as likely to seek out "enhancement" treatments as average or smaller-sized men! This suggests, at the very least, that male anxiety about "size" is about waaay more than size. (Further aside: I'm... pretty certain this anxiety is what drives so many men to email or post penis photos to dating sites, Tumblr "ask" boxes, etc.)
Anyway, as Kaili Joy Gray points out in her DailyKos post, Rush Limbaugh, Rep. Alan West, and other winger-est of the wingers evidently sincerely believe that feminism isn't just "emasculating" men, it's actually making our pee-pees smaller.