It is okay if your baby falls asleep on you when they are in infancy stages. You have to remember that you were pregnant for 40 weeks if you went full term and the baby has been inside of you. Now the baby is out and is not used to be on its own away from you. Also, having an infant lay on mommy, skin to skin, actually helps regulate their systems, their respiratory system, their immune system, their nervous system. Babies sometimes get out of sync with their bodies so when they are next to mommy and they feel the breath of mommy, they feel the heartbeat. It actually can help them get this is what my body is supposed to do. So you don´t need to worry about creating a bad habit from letting your baby lay on you or fall asleep on you. I would not recommend doing this when it is time for you to lay down and rest just for fear of dropping the baby or rolling over on the baby. But if you are awake and you are watching your favorite soap opera or what have you and the baby is peacefully napping on your chest, there is nothing wrong with that. Don´t worry. It is totally fine.