Why does your little Cancer cry at goodbyes and then immediately demand to know what's next? That's the Water-Fire push-pull at the center of this combination working exactly as written. Cancer's cardinal drive wants to build — safe attachment, a known home base, people who reliably show up — while the Sagittarius Moon keeps lobbing emotional firecrackers into that carefully tended nest. Your baby doesn't just feel things; they feel things and then immediately need those feelings to go somewhere, to mean something bigger, to turn into a story or an adventure rather than something they sit still inside.
The tension shows up in small, specific ways: this is a baby who can sob with genuine grief over a dropped toy and then laugh uproariously thirty seconds later, not because the feeling wasn't real but because the Sagittarius Moon burns fast and moves on while the Cancer Sun is still composting the experience underneath. Water dampens Fire, but it can also redirect it — so expect emotional intensity that is surprisingly mobile, not pooling and stewing the way a Cancer with a Water moon might.
What your baby's rising sign does is determine the container all of this pours into. An Earth rising will slow the Sagittarius Moon's restlessness and make the Cancer Sun feel more visible; a Fire or Air rising will amplify the philosophical restlessness and let the softer Cancerian core stay more private. Every one of those twelve versions is a genuinely different child — but the Water-and-Fire heart of this pair stays constant.