I was a month shy of five years old when my brother was born. Within fairly short order my parents put me to work keeping him entertained. My job was to sit on the couch with my brother resting against my arm and the arm of the couch while he sucked on my knuckle. I was the human soother. It was a brilliant piece of parenting strategy on the part of my parents.
When our youngest was three weeks old she was having a fussy day and we tried several different strategies to get her to sleep.
My wife was out running an errand with our five year old while I was home with our seven year old and 3 week old. We are hanging out and after I managed to get our newborn to fall asleep I transferred her to the care of my seven year old. They sat comfortably together for a few minutes before our youngest woke up again and was crying and fussing. We decided to try her soother and then suddenly I remembered the knuckle strategy. I suggested doing that and my oldest was eager to be a big sister and try it out.
We had to do some adjusting since big sister was kind of feeding her sister a knuckle sandwich rather forcefully and that wasn’t going over too well. Once she eased off and was more relaxed about it her sister took to sucking her knuckle with enthusiasm and within a minute or so, she was asleep. It was magical.
I made use of this strategy quite frequently over the next several months. With three daughters I had two human soothers on site who were always looking for opportunities to do some big sister work. As human soothers they participated in calming their baby sister and my partner and I were able to get other tasks done that needed doing to keep everyone clothed and fed and in a periodically cleanish house.
Parenting hacks and knuckle suckers for the win!