Hip-hop albums are big, of course, on guests and cameos. With an institution like Snoop Dogg, it’s getting to be like the freakin’ Bob Hope Christmas Special. Willie Nelson strums and trades verses on “Superman,” about learning your limitations. A clip from Snoop’s interview with Larry King turns up on “Gangbang Rookie.” R. Kelly, Kanye West, Wiz Khalifa and a Yaz sample help fill out the 80 minutes. Like Jay-Z, Snoop raps casually as if the beats were trying to keep up. “Wet” conceives an autotune aphrodisiac that gives the next track “Take U Home” extra horndog authority. Groundbreaking this is not, but his personality makes for splendid showbiz.