This is about writing, but for irregardless in speech, it works for me, too.
If shitlessness is too taboo for you, there are other ways to jar and unnerve your potential readers. Take pains to pepper your prose with irregardless, for example, and watch the hate mail pour in. Jennifer Schuessler writes, “Irregardless is one of those words that people love to hate. No one is lukewarm about irregardless. I don’t use it, but what I love about it that it has hung around on the periphery of English for over 200 years. It’s like this barnacle that you can’t get off the hull of the language, and I think that’s great.”
via Paris Review