When we were kids, my younger brother suffered from constipation and often needed an enema. Unlike me, he hated the enemas, so every time Mom was breaking into a sweat to give one to him.
On one of those occasions, I boasted to be much more brave of him and convinced Mom to give an enema to me to prove it. Of course I took every last drop without a word as a perfect patient so Mom, in face of my capricious brother, covered me with a lot of praises and compliments.
Evidently this was a blow to his childish self-esteem since soon after, though clenched teeth, he let himself give his enema without a fuss.
From that time on, given the positive reception of my little brother, in other occasions I got an "encouraging" enema (usually just a bit of simple warm water) in his presence. Every time - of course - Mom pointed out emphatically my behavior with comments like these:
«Honey, it doesn't hurt, doesn't it?» ; «My sweetie, you're so good, I'm proud of you!» ; «Did you see, Leo, how good is your sister? She took her whole enema without complaint, just like a big girl!».
Oh, how much I liked all that!