The forced fusions were glued together shards. The only thing we know of that is capable of gluing objects together is Rose's Tears and Steven's saliva as shown with Lapis. The shards we know of were seen inside of a Rose Quartz bubble. Rose is left handed as shown when she uses her sword and when by her pink pedestal. The kindergarten also has a pedestal. A left handed one. Rose made the forced fusions. She had access to the left hand pedestal. She had access to Crystal Gem gem shards. She had access to powers that could glue gems together and keep them alive. Rose may not be who we think she is.

Thank you to FandomTrash13 for your help on figuring this out! It was really appreciated!