Satsang refers to the fellowship of devotees who seek spiritual unfoldment by gathering to discuss Truth. This discussion of truth (which is synonymous with God) usually takes the form of sharing personal and divine experiences with the company of other like-minded sadhakas (a devotee doing sadhana or spiritual practice).
Satsang is a stage where you may or may not see the Masterpower, but He is with each one of us. He hears (us). He searches the heart of everyone of us. He tries to resolve all problems of the disciples by way of His power, because (in Satsang) you are directly under His vibration. A Satsang is a place, where the negative has no effect at all, where Master has a free will to give you any type of grace which is needed for you either in the worldly way or in the spiritual progress. He knows better what to do, what to give and what not to give. Satsang is a place where you need not worry about your shortcomings, where only devotion plays a big role.