In grade school, of course.
Not since I turned 25. I advise the more insistent clawfingers that if they pinch me, I will punch back, so that we'll both have a nice bruise. I once wore orange, deliberately to annoy the more self-righteous not-really-Irish.
I'm Scots, by predominance, with some Norman and some Welsh, but my mom's second husband was Irish, and so my half brothers are part Irish.