Board Thread:Questions and Answers/@comment-93.36.207.144-20130923115606/@comment-50.137.138.216-20131123020634
From Podpedia
It's obviously because he listens to Metallica when he's pooping and his favorite soung is Wherever I May Roam
BM=Bowel Movement
Vagabond= A synonym for nomad used in the song Wherever I May Roam