Spelling of Donuts and Gurgling and Trouble Googling

I wanted to quote Homer Simpson for a comment in a blog post. Anyway, in order to quote him I needed to know how to spell that gurgly sound Homer makes before he says "donuts" in his trance-like slow manner. So I tried to google it. Certainly there must be some sort of spelling for that sound out there on the web, right? The problem I had is that when I put the word "spelling" with "donut", all I get is stuff about the donut vs. doughnut spelling. So I am left not knowing how to spell that gurgling sound.