To have
sex or casual relations with someone you
work with. The consequences are risky; that you
will be caught with 'company fish' or potentially loose your job, or just be stuck working in an awkward situation.... but you do it anyway.
"Damn, that boy is
hot! Ima hit him up at the staff party!"
"Yeah he is, but I
never fish off the company pier. After the last guy, we had a crazy fight in the lunch room
later. I learned my lesson!"