Do's: Be honest with each other from the beginning
If you haven't done that, try to show your friend finders in the friendliest way possible that you enjoy the hookup time with her, but you don't want to develop a serious relationship at this time. Here are some examples you can say:
"If you still remember that we have talked about it from the beginning that we are only in adult dating. You are great, but I think our chemistry and personality are not suitable for getting a long-term relationship."
It is important to express your compassion, but let your adult friends know for sure that there will not be a serious relationship between you two. Don't make them hope and wait for you.
Don'ts: continue to have casual dating with them
Even if your hookup partner agrees that she/he can accept a casual hookup relationship, remember that they may not be completely honest with you, or they just don't want to lost you, so they decide to pretend to be fine as your adult hookup partners. They try to lie themselves that everything will be fine. Well, the fact is not.
In casual hookup, if one or both parties do not want to take it seriously, then this adult hookup relationship will inevitably fail in any way, so when someone fall for the other, it is best to break up completely. Don't depress your emotions and feelings, it will only hurt each other in the end.
Because your hookup partner is experiencing fascination, when she/he thinks of losing your pseudo-romantic relationship, she/he will feel that she/he is going to experience a withdrawal, she/he may continue to hook up with you, and continue to enjoy all the romantic moments they can get. Or, they hope you can change your view of the relationship between you. Continuing to be with her/him in any romantic way will only ignite her desire fire.
If your nsa finders tell you that they are free to date and tries to convince you, you can say this:
"I'm so sorry, I can't do this anymore. It will only make each of us uncomfortable and uneasy. As I have known what you want, I can't pretend it is okay to hook up with you. I don't want to hurt you. If we continue to do the same thing, I will always worry that you are looking forward a serious relationship that I can't give to you. "
Be polite and compassionate, but stand firm. Do not cause later tragedy because of temporary softhearted. Your friend find is kind and hot, maybe you two are quite in tune when it comes to hookups, it doesn't means you two are good to be a couple. Don't force yourself to do anything you are not prepared.