We have been trying to tell our kiddos that Little Kitty needs her space and you need to be careful with her belly. The older children understand this and treat her gently. Youngest child, not so much. So, to get him to understand I used my nonperfect parenting skills to the max.
Youngest child spends most of his mornings pushing his baby stroller around our living room and feeding his baby doll that cries when it wants it's bottle. Youngest currently believes he and Little Kitty have screaming baby dolls in their bellies. I need work at the mommy thing or at least work on my wording for kitty pregnancies.