After earning his first Oscar nod for “Winter’s Bone” nearly two years ago, John Hawkes could’ve cashed in, accepting one of the lucrative offers that, after 25-plus years of steady character-actor work, were finally coming his way.Instead, he signed on to indies such as “Martha Marcy May Marlene” and this year’s “The Sessions,” the option with the smallest budget. “I don’t need a lot of money,” Hawkes says. “It met the requirements I look for: A well-written script and a character who matters to that story and is unusual.” Mark O’Brien definitely isn’t your typical Hollywood protag. A journalist and poet, he was a Berkeley-educated, Catholic Church-going polio survivor confined to an iron lung who decided, at age 38, to lose his virginity with the help of a licensed sex surrogate (and the blessing of his priest). To prepare for the challenging role, the Minnesota native immersed himself in O’Brien’s writings, studied the O’Brien-centric doc “Breathing Lessons,” and met with those who knew him well, including surrogate Cheryl Cohen Greene, played in film by Helen Hunt. He also spent countless hours learning to type using a wooden stick clenched between his teeth and even had “The Sessions” prop department craft a soccer ball-sized piece of foam that he placed beneath his body during filming to better emulate the curve of O’Brien’s polio-ravaged body. “I wanted to make everything second nature so I could forget it all (on set) and just be present when the director called action,” says Hawkes, who ultimately injured a disc in his back, an ailment that persists but that he shrugs off. (One upside of spending most of the film lying down? “I was always on my mark,” quips Hawkes.) The result is a pitch-perfect perf that garnered standing O’s at Sundance and talk of another Oscar nod. “It makes me nervous,” Hawkes admits. “I’ve been able to enjoy a reasonably normal life in the circus, but it’s getting harder.” But perhaps, a little more golden.