Peeping over the wall
Peeping over the wall, a Chinese idiom, Pinyin is y ú Qi á ngku ī P í n, which means cheating between men and women. It's the same as "going over the wall and drilling holes".
The source of the idiom is Mencius Teng Wengong Xia: "if you don't wait for your parents' orders and the words of the matchmaker, you can see each other through holes and follow each other beyond the wall, then your parents and Chinese people are cheap."
Peeping over the wall
There are three unknowns in this - cǐ zhōng sān mèi
Shoes bow and socks are shallow - xié gōng wà qiǎn
learn about customs and habits of the country one goes to - rù guó wèn sú