*You need this invisible crib mod*
You can place the lounger on your sim beds and place the baby into the lounger use the "ALT" key for perfect placement.  If your sim isn't able to interact with the baby you need to move the baby closer to the edge of the bed. You can use the in game pictures as a guide for where to place the lounger and the baby.
 
Version 1: 10 Swatches
Version 2: 3 Swatches
Found in "comfort" and also searchable in buy mode under "CSXO Baby Lounger"