Thank you for your interest! Let me explain better.

Foreigners assume that Japanese people are homogeneous from our outsider lens. However, since there are 47 prefectures in Japan, regional variations, such as personalities, exist.

Osaka people are known to be more money-minded (that’s another story for another day) and funny than the average Japanese. Many of the country’s famous comedians hail from Osaka. People from other prefectures flock to Osaka to watch standup comedy acts (my wife and mother-in-law did so).

ゆるしてやったらどうや Is a phrase popularised by a comedian. It isn’t the standard Tokyo variety either; it’s instead an example of Osaka dialect. It isn’t an idiom passed from generation to generation in that sense. I think a better equivalent in English is “cut me some slack!”

The killer punch to make people laugh with this line is the intonation. In which I deliver it. My ex-students made me practise and practise until I got the intonation down pat. And it worked for that dinner with my wife’s cousin’s family haha.

Sometimes the timely use of a word/phrase helps to break down the distance between people really quickly. That’s what I like to do haha.