When the Keegan came home I was so surprised with the way he and Charis behaved. Charis and Keegan would fight over me and over their toys. I found this totally unacceptable especially since my cats did not do this. I started teaching them how to share.
First I had to show them that they can still have fun even if I play with them together and this gave them an idea what the word share meant. The next thing I taught them was how to share their toys with each other (see photos). So far the only thing they really don't share is food - which is good because they both have different dietary requirements but they don't have fights over it either. There will be times they will forget and I will hear them (esp Charis) give each other a warning growl, I quickly remind them to share. They have been pretty good with it.