Fe-Si-Ne-Ti
The auxiliary function for ESFJ's is Si. Unlike ISFJs, who have Si as their dominant and Fe as their auxiliary, ESFJs have them opposite. So, dominant Fe basically wants everything to run smoothly and everybody to get along, it wants to maintain a sort of cohesion. A side effect is that Fe forgets to account for individual differences because it feels as though it divides the group. Another reason for this is that it doesn't like other people, or even themselves, to be left out. Auxiliary Si's job, therefore, is to remind the user to look inside their own experience to make decisions for once. Si will remind them to step out of the bounds of collectivism, and consider that everyone has different needs because we're all different. When Fe is at its unhealthiest, Si will be ignored (not completely, you cannot completely ignore a function and this is what makes them so twisted when they are unhealthy,) and will begin to think of people as one cohesive whole, like a big pink circle with no other color. If you put too much attention onto Si, then it will become pedantic and hung up on the smallest details. It will also cause you to become obsessed with doing everything by the book. Again, you must balance these two functions together to become a more healthier person.
The tertiary function for ESFJ's is extraverted intuition, otherwise known as Ne. Tertiary is an undeveloped function for childhood and adolescence, and doesn't really start developing until sometime in your 20s. Tertiary Ne can cause one to be close-minded, remember that one does not to typically use their third function. Ne works off of Si here by creating new ideas based on past experience. Ne is very mysterious to ESFJ's, they are not really known for the abstract thinking that high Ne users have, but this can change the longer you develop your tertiary function.
Lastly, the inferior function here is Ti. Like inferior Te, Ti in this position is disliked by ESFJ's because it can shatter their expectations and their view of reality, and also because Ti is a very fuck-your-feelings function and can be viewed as offensive. They do not want to offend people and certainly do not want to weaken the group harmony. Again, very much like Fi doms do, they will use Ti unhealthily to defend the poor worldview that results when one relies on Fe too heavily. One example of what happens when Fe doms don't control their Fe is not creating boundaries with people and overextending themselves because they don't want to hurt people's feelings. What also happens is that they burn themselves to keep others alive. Undeveloped Ti will mess with Fe's ideas of interconnectedness and harmony, any sort of breaking away those connections will be met by dysfunctional Ti usage (example: "us vs them" thinking and becoming overly critical/judgy) if they don't learn to use Ti in a positive manner. What happens when Ti is developed is that they can create a healthy model for problem selving based on Ti critiques and guidelines, and will help you to think more clearly when you are stuck in that overly-critical loop of Fe gone rogue.
Fe-Ni-Se-Ti