Ukrainians, descendants of that culture, have a proverb "Happiness is a neighbor's house burning". Which is not far away from everyday vibes and the way of life overall.
So we may have way simpler explanation here.
self mutilation is said to have been practiced by priests of certain obscure cultures like the old prussians and other slavs. They also cremated their dead.
Pretty ambivalent, IMHO, if house burning could be punishment shrugged off as a very humbling tribute. I think it is very very unlikely that stuff like castration or even just flagalation had started out as a voluntary practice.
So, yeah. The way I know a similar joke in German: The two of you get two wishes and a lashing. What will it be? The first said, a pot of gold and please grease my back so it doesn't hurt so much. The other replied: Gimme the other dudes gold and bind him to my back.
Plenty of variation on that one and I probably misremember it as well.
