The Browns need to tell Johnny Manziel to slow down. If they’ve already delivered the message, they should do it again. They should do it every chance they get because, well, the celebrity rookie continues to party every chance he gets. A month ago, I defended the trip Manziel took to Las Vegas during Memorial Day weekend because I believe Johnny Football could let loose poolside and even spray champagne into a crowd at a nightclub in late May without those activities precluding him from becoming a successful quarterback for the Browns. But I also wrote that Manziel would deserve criticism for having his priorities out of whack and lacking commitment if he continued to tear it up with great frequency. Since the Vegas vacation, Manziel hasn’t taken a weekend off from partying. His living-life-to-the-fullest streak extended to five consecutive weekends when he went out Friday, Saturday and Sunday in Houston, as documented on social media and then passed along by published a photograph of Manziel drinking from a bottle of champagne Sunday while watching the World Cup in a pub and sports bar. He was in Houston the previous weekend, too, barely able to keep his eyes open as he pretended a stack of cold, hard cash was a phone while dropping an F-bomb on video. Let’s not forget the bottle of alcohol atop an inflatable swan the weekend before in Austin, Texas, and the Los Angeles nightclub rendezvous with rapper Drake while in town for the NFL Players Association Rookie Premiere late last month. We’ve reached the point where some of you will scoff — if you haven’t already — because there have been no indications that Manziel has done anything illegal. He’s 21 and many people his age party and drink on a regular basis. I readily admit I was one of them. But I never received an $8.25 million contract to play quarterback for an NFL franchise. Yes, New York Jets great Joe Namath won a Super Bowl and became a Hall of Fame quarterback despite acting like a wild man in the ’60s and ’70s, though it’s hardly a recipe for success. This week, Manziel should receive valuable reminders along those lines. The NFL Rookie Symposium is underway in Aurora. The NFC players arrived Sunday and will be schooled through Wednesday. Their AFC counterparts, including Manziel and the Browns’ other five picks from this year’s draft, will arrive Wednesday and attend the orientation through Saturday.