How can I walk normally?

People make fun of the way I walk all the time, I never get what they're saying they make minor comments like "He Walks Funny/Strange" And one time one of them had the nerve to say "It looks like he got something stuck up his bum when he's walking" And I cannot understand them. But It's true ALOT of people tell me I walk strange, Is it because I'm flat footed? Sometimes I walk on my tippy toes aswell, can someone please help me or show me a method on walking normally, with FLAT feet. I mean my foot has no ARCH at all, I have the flattest feet in my whole family, sometimes my bro's/sis often call me .. whale feet or platypus feet, or boat feet, which I find rather funny and not disturbing at all because they are my family. But no one outside of my home knows I have such flat feet, is this the cause of my funny walking by the way?