It's just a forward roll with your feet backwards. If you can do a good forward roll, you should be able to do it. It's handy for when people do a strong tenchi-nage for instance.
Yeah, this is what it looked like to me too if I'm looking at the right parts of the videos. I don't know that I'd think of it as a different kind of ukemi, more just learning to rotate quickly and smoothly into a forward roll. I'm curious though if that means the original poster's dojo doesn't do forward rolls? Because that would be very curious to me and I'd wonder how they handle forward projections (say kaitennage for example). Unless it's just the rotating entry to start off the roll that's unfamiliar.