My son has been putting his hands in my mouth since he was 4 months old. He is now 2 years old and is still doing it right before bedtime. My question is how can I help him break this habit?
I cared for a toddler once whose habit was to suck his mother's earlobes. She had the same issue, only her earlobes had become so disfigured that she could no longer wear earrings....
Behaviors take on a life of their own and become habits because they are comforting and familiar. Your son is enjoying this routine as well as the time with you. The trick is to substitute another ritual that still provides both those things. Songs, snuggles, bedtime games all accomplish this.
The real trick, and by far the hardest part, is to make the decision to stop the habit and then stick with it, even under great protest from your son. Everyone else in the family should support your decision as well. Giving in just once or twice only teaches him to protest harder. Usually, habits in toddlers can be changed in days, or with particularly stubborn babies, a few weeks.
Make the plan, stick with it, and you will thank yourself in the future.