Target brand 3 month diapers (best brand for cute boy designed diapers and we went with 3 month because a lot of people tend to gift newborn sizes and you only need those for a little while)
Rubber bands... LOTS
Ribbon (6+ yards)
Large baby powder
Stuffed animal topper
Pacis (to decorate)
Socks (to decorate)
Start by rolling the diapers... you will need around 75-80 total. This whole thing is approximate as each one is a little bit different. I rolled against the current "bend" in the diapers.
Wrap a rubber band around the middle of the rolled diaper.
After you get enough rolled, you will need about 45 for the bottom layer, use a large rubberband and begin stacking them around the baby powder. Fill the rubberband to be nice and snug, and get the shape pretty circular. Make sure that on the outer layer of diapers the "end" of the diapers is on the inside, so that it looks nice & smooth.
Begin the next layer with the top part of the baby power. This layer is about 25 diapers. Again wrap a large rubber band around all of them. I start with a few, put the rubber band around it and continue to add more in there to fill it out.
For the top layer, put the bottle on top of the baby powder, and put 6-8 diapers around the bottle, again wrapped with a rubber band. In order to make these stay well, we used the toothpicks connecting the middle of the layers.
The cake itself is done, time to decorate. Take the ribbon, put it around the middle of the base layer, and pull enough to have room to tie a bow in the back.
Do this on each layer. Doing a bow allows you to pull the ribbon nice and snug to help hold the diapers together and also looks pretty.
Top the cake with the small stuffed animal. We sat him on top of the diapers on the top layer, "hugging" the bottle. He is secured with a rubber band around his back, under his arms and around the bottle.
Add the pacis and socks as decoration, wherever you feel like squeezing them in. You could do more or less decoration.