Coming home — even to a second home — can be difficult. For Jae Crowder, it started with having to trot out a rather woeful rendition of “Happy Birthday” for Elton Brand, who turned 34 on Monday. Crowder and fellow rookie Bernard James had to belt out the birthday song and, by coach/pianist Rick Carlisle’s rather lofty musical standards, “it was awful.” But for Crowder, the stay in Milwaukee got better. He was hooking up with friends from his two seasons at Marquette, just a mile or so from the Bradley Center, where the Mavericks practiced Monday and will play the Bucks on Tuesday night. Crowder said it was a little weird walking onto the arena court Monday. “The last time I was here, I played my last college game here. This is my first time back since,” he said. “It’s a surreal feeling being in the NBA now and being back here. This is my home court, basically. It’s a great feeling.” That last game at the building that Marquette and the Bucks share was a memorable one, by the way. Crowder had 26 points, 14 rebounds and five steals in an 83-69 win over Georgetown on March 3, 2012.