'Splain, as a contraction for “explain,” has long been with us, but I originally began to appreciate its comic potential in a creative writing workshop in graduate school. The inestimable Steve Johnson had submitted an uncharacteristically inscrutable poem, and after we all had contorted our minds trying to figure it out, we finally just turned to him and asked, “Steve, what in the heck does this even mean?” With total composure and deadpan wit, he replied, “I just write 'em. I don't 'splain 'em.”
Recently, and particularly in the form of snarky political commentary on sites like Gawker and Wonkette, 'splain has become a suffix, attached to the clumsy and often clueless attempts by conservative politicians to speak on the experiences of women and minorities. Thus, we have such constructions as, “Ted Cruz attempts to man-splain women's reproduction,” and, “Ann Coulter tries to white-splain American racism.”
Some purists may object that “man” and “white” don’t sound anything like “ex,” so we're not even talking about very good puns here. But I think that misses the point: the very wrongness of 'splain in these contexts mirrors the wrongness of people trying to speak outside of their own experiences. In this way, 'splain, as suffix, sacrifices the pun for the sake of the satire-- which is, I might add, the more worthy cause.
I should end before I am accused of 'splain-splaining, but 'splain as suffix could maybe only happen in the postmodern age. Its use displays a knowledge of pretty highbrow feminist and cultural-studies theories, and never before has theory so easily mixed with popular commentary. This kind of po-mo pastiche is only accelerated by the wild and woolly world of the web, where speed and sarcasm push language to its limits.