Each one of us, every spirit has an aura emanating from within our spirit. If we are filled with the Holy Ghost, we have a bright and glorious aura emanating from within our spirit. This is how Satan, who does not know our thoughts, can determine that his mental attacks on us are working. If we accept his enticements and think evil thoughts, our aura diminishes. If we resist, then we remain pure and clean with a bright aura.

What I understand President Faust saying is that even though we make choices alone or in our homes or even in our own minds, the decisions we make have consequences that effect in one way or another everyone else. We don't control anyone else, but collectively as an individual, family member, community, country or planet all of our choices (obviously some have greater effect at different levels than other choices) carries with them universal consequences.

As an example, what one eats may seem "private" but that decision can carry unintended consequences, such as those who produced those food items will need to produce more to keep up with supply and demand. If we grew it ourselves then those who produce the same food stuffs cannot produce as much since there will be one less purchaser of those items in the marketplace, too much supply and not enough demand. I can choose to have a greenhouse on my property and grow my own food, but if everyone did that worldwide there would be no more farmers or markets nor trucks and truck drivers needed to transport from farms to markets either. This example above is not a bad thing, but it will carry with it quite far reaching consequences for society as a whole.

As far as immorality goes, choosing to be promiscuous has negative consequences for not only the participating parties but for society as well. If one or more participants has a STD that could be spread to someone else, or an unwanted pregnancy could occur. Serious violations of our conscience, like immorality, effects our thoughts and decisions far beyond the "private acts" involved. Most people would agree that what someone or people do behind closed doors is there "own business"; nevertheless there are consequences that effect us all in one way or another.