Expert Fisherman
Someone who jacks off a lot. Originates from the term "mastrubater", which sounds a lot like "master baiter".
Q "Dude, why is your roommate talking to that hot chick Jenny on the phone in the bathroom?"
A "What can I say, dude- he's a real expert fisherman"
A "What can I say, dude- he's a real expert fisherman"