How can I put the rubber gasket on my front loader back on?

I have an LG WM1814CW, & have a new rubber gasket (or boot) for the door of my washing machine bc/ the old one is mildewey & crusty.....I got the old one off, & I know about the 2 rings that hold the boot in place, my problem is that I cannot seem to get it to "fit" around the inside lip. I can get it all around except for about an 8 inch span, & when I try & put that on it pops out elsewhere... is there a secret or tool to help???