This pose is called In and Out and is a great first yoga pose for babies. It helps them pass gas!
First, you place baby on their back, as you can see we are just on the floor, but you can use a yoga mat if you want.
Always ask your baby if they want to do yoga first. They understand way more than we give them credit for, and they will let us know if they are not in the mood.
Then you start by holding onto their legs, anywhere that feels comfortable to both of you. And then you bring their legs to their chest, like so and gently press into their stomach…the combination of the pressure and movement helps them pass gas.
Then you extend their legs out like this. You say what you are doing as you are doing it. As you bring their legs in, say Iinnnnn! And as you bring their legs out, say Ouuuuuttt! You want to say in a sing-songy fun voice. Sooner than later, they will learn to associate the word you are saying with the movement, and thus you are also helping them with their language development!
Do In and Out several times, till your baby wants to do something else!
You can find this yoga pose and more in Itsy Bitsy Yoga by Helen Garabedian.