Country singer Pat Green took the stage at the Troubadour Festival in Aggie Park. There, he was joined by a special guest when Texas A&M baseball coach Jim Schlossnagle made his way onto the stage with a guitar. Schlossnagle ended up playing guitar alongside Green for the final song of his set, “Wave on Wave.” On top of that, Green also said he’d been to the Texas A&M baseball game earlier in the day. You can watch as Jim Schlossnagle joined Pat Green on the stage, here: As he comes onto the stage, Jim Schlossnagle appears to be teaching Pat Green a new hand signal. It’s one that most Aggies a…