Baby’s heart is a balloon that she carries wherever she goes. You need to protect her heart-balloon from the dangers of the world by avoiding sharp things and ensuring she doesn’t let it fly away.
She does a perfectly good job of protecting her body by flat-out refusing to do things that scare her. Try dragging her across a pit with a tentacle flailing out of it and you have no chance. Instead, you swipe the rear touchpad to find a backdrop that will scare it off.