Two fun ideas that you can easily use if you're going to tell the Bible story where the pregnant Mary meets het elderly pregnant aunt Elisabeth.
A visit from a big tummy
If you know anyone who is pregnant, you could invite them to come and talk to the children about what it’s like to be pregnant. Has she ever felt her baby dancing in her tummy? Maybe the children would be allowed to touch her tummy and see if they can feel the baby move.
Fill a large plastic tub or small paddling pool with a layer of water and lots of washing up liquid. Give each child a long straw and see how many bubbles you can make together by blowing into the water.
Tell them beforehand about how this story tells that Elisabeth was filled with the Holy Spirit. Just as the air we blow through our straws makes more and more bubbles, so Elisabeth is filled more and more with the Holy Spirit, and is full of joy because of the wonderful news that Jesus is going to be born.
Make a great big mountain of bubbles together!