Is it normal to go by my nickname at work?

I manage investment portfolios for Fortune 500 companies, so professionalism and image are very important in my job. Despite this, many of my colleagues have taken to calling me by my nickname in front of clients. My nickname is Girth E. Johnson, on account of my monstrous, Pringle can sized schlong. During meetings, the fabric of my pants stretches so tightly across it that you can see every curve, every vein, every goddamn pore of my magnificent, titanic ding-dong. Male and female clients alike will stare directly at it, mesmerized until they feel compelled to end their life on a high note by choking on its immense G I R T H. Sometimes I fear this power that I wield, but I sleep well at night knowing I wield it righteously