Wait, why can't you type a paragraph at a time in IRC?
But even then, paragraph-at-a-time is hard on IRC because there's a max line length that's surprisingly short (and usually just truncates the rest of your message once you exceed it!), and just because you'd stand out as being the person writing much more than everyone else and being slow to reply. IRC simply isn't a medium designed for carefully considered thought like that.
"Sorry this is so long. I didn't have time to make it shorter."