FRANK Bruni enjoys more than just a good steak. During a recent performance at Joe’s Pub, comic Billy Eichner recounted in graphic detail a one-night stand he once had with the former Times restaurant critic, whose book, “Born Round,” is now on shelves. Eichner even recounted what he called Bruni’s “oral fixation.” An embarrassed Eichner told Page Six, “I was drunk and Frank was a perfect gentleman.” Bruni says, “A gentleman never tells.” Eichner’s show, “Gay, White and Terrified!,” runs Oct. 13-14 at Ars Nova theater.