We can have lots of splendid ideas about how to interact with the people we live with, but in the heat of the moment, concrete examples are sometimes more inspiring than abstract theories. They can perfectly well be made up, but being concrete can really help.
Abstract theory: doing something to my child against hir will damages hir, damages me, and damages our relationship.
Concrete example related by friend: "Our child had awful teething pain and was crying and crying. When I tried to give hir infant paracetemol, se closed hir mouth tight and turned hir head. So I said 'Mmmm, yummy' and licked the spoon, and then se drank it all up and wanted more".
In the moment: preverbal child has (*thinks for a hypothetical*) such a ghastly tummy bug that the doctor prescribes a suppostitory (*do doctors even prescribe suppostitories any more?*). The very prospect of inserting said suppository is ghastly. I'm assuming that the parent's best theory is that the child definitely needs the medicine. The most likely thing is that the parent will grit their teeth, hold the child down and do the deed, giving lots of hugs and apologies afterwards (but the child won't associate getting better with the 'necessary evil' of being held down and having medicine pushed up hir bottom). In that stressful moment, ("I know it's going to bloody hurt my child and our relationship, but what am I supposed to DO??? MY CHILD NEEDS THIS MEDICINE"), the model of the friend's anecdote might help one think creatively more than the abstract theory.
The anecdote might just get one thinking of parallels. I'm not suggesting that one should attempt to jolly the child into wanting the suppository... it's not quite the same as a painkiller in a sweet suspension... but instead of thinking "I have to do this right now, even if it hurts my child", wait for a good moment. Find a way of distracting the child during a nappy change so they hardly notice? Or when they are just out of the bath? Or maybe when they are asleep?