I first saw the topponcino in the Michael Olaf catalogue and thought holy overkill! It is a small pad that you are meant to hold the baby on and also for sleeping. After reading this post on the very informative The Full Montessori blog I decided to make one before the baby was born.
I made it out of thin foam and my mom sewed a cover for the foam and also a washable cover.
For a tutorial see this post.
For the first two months after Baby J came home we both slept in his room. I had a mattress next to his floor bed. At night I would put him on the topponcino to feed him on my mattress and when he was done just slide him on the topponcino back onto his bed. This enabled me to not wake him as the warmth and consistency of his surface never changed. It worked like a dream!
I would now say this is an essential piece of equipment for any new parent! So easy to make and inexpensive but a life saver.