By Andrew Holleran The NASCAR world was treated to a now-rare look at Dale Earnhardt Jr. behind the wheel on Friday evening. Earnhardt Jr., who’s retired from full-time racing, competed in the NASCAR Xfinity Series at Martinsville Speedway on Friday. The veteran NASCAR driver finished in 11th place. Earnhardt Jr. appeared to enjoy his once-a-year night on the track. Dale Jr. had some advice for tonight’s drivers, too. “My hope is that at the end of todays race a driver gets out and drinks a couple cold beers and discusses the fun he had getting the donuts that are on his door,” he tweeted. Wel…