The 1st house (Lagan) represents the physical body and the outward personality. The Moon (Chandra) represents deep emotions, sensitivity, and vulnerability.
When the Moon sits in the 1st house, the person becomes incredibly sensitive, but they develop a powerful defense mechanism. Dr. Sharma explains that this person will hide their true feelings from the world ("chhupta chhupata rehta hai").
No matter how much pain or depression they are in, they will put on a brave face and smile at everyone ("baakiyon se muskurata rehta hai"). They will only reveal their true, vulnerable heart to one or two deeply trusted people.