Unfortunately, I don't think there's any (public?) way to force it. I've seen the feature disappear or reappear on a reload -- it's not consistent across a session, let alone on a user-by-user basis.
Try refreshing the home page until it shows up, maybe?
At youtube.com/new, they say you can opt-in to experiments if you have premium, but I don't have premium and am not sure if that is one of the options.
Interestingly, I think there are a couple of variants for the number of videos to display on the home page, too.