Both my boys were self soothers (read: finger/thumb suckers)
I think for the most part, is because like all new "new-aged" parents, we read and overthink too much about how to raise our little ones before they have even arrived. You know... the age of 'pacifier is bad', ' baby walker is dangerous', 'sleep training is good', 'letting your baby cry it out is bad' etc. etc.
There is so much information available these days, it really just depends on what you want to read and which information you like to take on. For us, I guess the biggest fear those readily available baby information had given us had to be "all thing bad about pacifier". We refused to let either of the boys have a pacifier in their infancy, for fear of what it would do to their teeth later on.
So with the absence of a pacifier, both the boys found their own soothing tools very early on. H used his middle and ring fingers, a bit like a rock star hand; whereas Z was a more conventional thumb sucker.
It was all good, right? Without the pacifier, it means we don't have to be woken up by crying babies looking for their "dum dum" in the middle of the night. That their teeth will be beautiful for the rest of their life?
Nope. The issue with selective online researching was, while we learn more about how pacifier is not ideal, we forgot to also look into the issue finger/thumb sucking. Because the teeth ruining problem is exactly the same for a pacifier and its substitute thumb/finger.
This issue started becoming very pronounced when H turned 3, after more than 2.5 years worth of finger sucking, his jawline and teeth had started moving and changing shape. Needless to say, we were mortified. So we started trying to wean him off his finger... But with the finger being attached to him and not something we would like to chop off and throw in the bin like you could with a pacifier, the process was long and painful. There were a lot of setbacks and tears. We tried everything! Words of encouragement, cautionary tales, videos showing what continued finger sucking would do, even a much too disturbing story of "suck-a-thumb' had did nothing to stop him. H was a creature of habit and to give up his fingers that helped him go to sleep every night was just too much!
After all of that, what did it was a little tiny white lie. That and also a little tiny bottle of colorless nail polish. We told H that if he doesn't stop sucking his fingers, very soon the yumminess on his finger is all going to run out and he will be left with just yucky stuff. Of course the warning did nothing to stop him, but after a few weeks of repeating the same warning, one night, while he was sleeping, we crept into his bedroom and put on this horrible tasting nail polish that is marketed for people to quit nail biting. Predictably, 30 minutes later, there was this cry of horror from H when he went for his finger in his sleep and instead tasted this yucky finger his parents had been warning him about. There was so much tears that night lol. But thankfully, it all started going well from then onward. It took about 3 months of constant sneaky reapplying, but he finally did it!
Fast forward to 6 months later, we thought we would nip it in the butt early on with Z, except the nail polish did nothing for Z! Tried it again 2 more times with a thicker application, it still didn't do anything! We put it down to the fact that he was just a bit too young with taste bud that is not quite mature. And we were resigned to the fact that we will have to try it again when he gets older.
Surprisingly we didn't have to do it at all because a couple of months later Z decided to quit it all by himself, with no help from anybody. He did it all out of his love for his big brother.
H being a bossy big brother that had successfully quit his finger, he had begun monitoring his little brother's every movement. When Z had his thumb in, he would tell him off or call out to us to come give him a lecture (they share the same room). One particular night, there was a commotion going on in their room, so I went and check on them. When I opened the door, H was in tears with Z on his own bed looking bashful. Upon quizzing them, H told me Z was sucking his thumb even though H had told him off. In tears, H told me, Mummy i tried and I tried but Didi (means little brother) just wouldn't stop! I am scared he is going to turn into a rabbit face ( a little warning story we told him when he was still sucking his fingers). I had to console him and explain to him that Z is just a little too young, and not ready to quit just yet.
Surprisingly after that night, Z just stopped altogether! I think seeing his beloved brother so distraught had really bothered him and he wanted to do a better job for H. My hear is full of gratitude and joy seeing Z giving up his precious habit for the love he has for his big brother! And so much relief knowing I won't have to go through another weaning pain with him!