Which way to wear a Cummerbund?

Hi, I went to the suit rental shop yesterday to rent a Tuxedo for prom, and when the assistant was putting the cummerbund on me, he said that you wear it pleats down. Now I have heard before you wear it pleats up, to catch the crumbs when you eat. So this has made me confused as to which way I should wear it, so I thought I’d come here and ask.

So, do you wear a cummerbund pleats up or down?

Thanks in advance.