If you’re ever going to make a pass at Anderson “Silver Fox” Cooper — which you probably shouldn’t, since he’s happily living his life with Benjamin Maisani right now — know that there’s one particular topic Cooper will immediately kick you to the curb for if brought up on a first date. Bravo czar Andy Cohen learned this the hard way, when the duo were set up on a date a few years ago by a mutual friend. “Andy and I were first set up on a blind date, which never happened because we had a phone call and after two minutes I said, ‘I’m not dating this guy,’” Cooper divulged on Watch What Happens Live last night. The reason? One that’s pretty understandable: Cohen brought up Cooper’s mother, the fabulous socialite Gloria Vanderbilt, within the first moments of their first conversation. “He broke my cardinal rule,” Cooper explained. “He mentioned my mom within the first four sentences of meeting me. If somebody does that, it’s a deal-breaker. And we’re never going on a date.” The two are good friends these days and are currently bro-ing out in a year-long national tour, so at least not all was lost with Cohen’s faux pas.