Insecurity

It's okay to be insecure, but it's not okay to talk about it.  Referring to yourself as "Captain Chubster" and making frequent reference to your thin genitals doesn't make you seem grounded and jovial, it just constantly reminds people that you're fat and don't fill out your boxer briefs. 

Stick to dealing with your insecurities by belittling c0-workers and cutting.