As prison inmate Tobias Beecher on HBO's Oz, actor Lee Tergesen has made many viewers think twice before drinking and driving. On the jailhouse drama — whose fifth season kicks off Sunday at 10 pm/ET — yuppie lawyer Beecher is serving 15 years for killing a little girl while driving drunk. And talk about serving hard time: He's been addicted to drugs, sodomized by a neo-Nazi, had his buttocks branded with a swastika, bitten off one attacker's penis and defecated on the face of another!

"Playing Beecher can definitely be a bit of a mental challenge," Tergesen tells TV Guide Online. "I always experience sort of a hangover at the end of each season, and it can take a few weeks to get reacquainted with normal life."

What hell awaits Beecher this season? Though Tergesen won't rat out Oz's writers, he does reveal that Chris Meloni (Law &#038 Order: SVU) will return as Chris Keller, Beecher's kinky cohort. "People always stop me on the street to talk about the relationship between them," he says. "Even though both characters are f----d up, people seem to like the fact that they try to love and forgive each other."

In typical HBO fashion, Oz is fearlessly graphic, going as far toward embracing gay sexuality as any show this side of Queer as Folk. Tergesen — who wed his longtime girlfriend last summer — admits he was intimidated by that at first. "I've heard other actors say that kissing another man is the kiss of death," he says. "They somehow think it's gonna hurt their career. And I'll be honest... Initially, I was like, 'Oh my God, how am I going to do this?'

"But," he adds, "Chris and I got together to talk about it and decided to have no fear. He and I had just started working together the first time we had to kiss. By the time we did our third scene, it was really interesting. To let myself [be] open to that was emotionally an intense thing."

So who's a better kisser: Meloni or his wife? "Definitely Meloni," Tergesen laughs. "When I kiss my wife, I don't see any cash."