The next yama is satya, which means truth, &, like ahimsa, it's a self - restraint. We are restraining, actually, from being un-truthful, & instead we are working on being truthful, living our truth, keeping away from being dishonest & avoiding dishonest people & situations.
Sounds like a tall order. But, a lot of behaviour is involved, & rather than pontificating about truth, we are attempting to be it. And, although with the deeper more esoteric aspects of life, spirituality, & our psyche, we continually discover, on the spiritual path, that truth is an evolving process, we really do need to live a live whereby we are aligned in thought, emotion, and deed, moment by moment, day by day: 24/7.
When we are in a situation where we get a strong feel in the gut, or heart, or just a strong knowing, that we should not be in this situation, we should not be supporting it. We know (thought), our gut tells us (feeling) & we keep away (deed). That's how we do it. We don't have to justify....(couldn't find any justification in Patanjali's Sutras, one of the definitive yogic scriptures!!) But, of course, we are all so human.....how can we do this?? Might we hurt someone??? Should we say something??? Isn't that part of truth too??? Sometimes, we would not be believed, so we keep quiet....but you know, for the spiritual seeker, truth always finds a way of wriggling out into the open.
In situations whereby we are in situations that are not in accordance with truth, or we come face to face with a dishonest, or malevolent person, we can simply remove ourselves. If we personally want to have peace of mind, we need to, where possible, avoid people or situations, that cause us mental, emotional, or physical distress or distrust. That will reduce our stress levels, & make us feel better about ourselves.
And how do we talk truthfully? Well, we probably don't need to run around blurting everything, but we can 'be pleasant'. So, if we have to communicate where/when we are feeling upset in any way, just can just aim to state clearly & honestly, without harm or hate, & you will find it easier to have a truthful voice.
To live in truth, we must consciously avoid harm, to ourselves, or to others. We need to walk our talk, rather than appear to be one way, but secretly be a less truthful way. We don't have to be perfect, we just need to live some principles in a way that we can live with oneself. We can sleep easy at nights without having to scheme to cover any dishonesty.
For the sincere spiritual aspirant, truth is something that cannot be avoided. To embrace truth with an open heart will give you great rewards. You will also like yourself.