He is used to play western style boxing, the rules said no attack on genital organ, that's why he couldn't handle that sneak attack on his scrotum.
Examples (Wiktionary)
Mandarin
沐猴而冠
沐猴而冠
mù hóu ér guàn
a macaque wearing a hat
Mandarin
猴子爬上了树。
猴子爬上了樹。
hóu zi pá shàng le shù .
The monkey climbed up a tree.
Mandarin
正当猴子忙得昏天暗地之时,肥猫会突然提起猴子早就忘了的另外几件事,然后就鼻子不是鼻子脸不是脸的把猴子狠狠臭骂一顿。
正當猴子忙得昏天暗地之時,肥貓會突然提起猴子早就忘了的另外幾件事,然後就鼻子不是鼻子臉不是臉的把猴子狠狠臭罵一頓。
zhèng dāng hóu zi máng de hūn ti ā nàn dì zhī shí , féi māo huì tū rán tí qǐ hóu zi zǎo jiù wàng le de lìng wài jǐ jiàn shì , rán hòu jiù bí zi bù shì bí zi liǎn bù shì liǎn de bǎ hóu zi hěn hěn chòu mà yī dùn .
Just as the monkey was dazed and confused, the fat cat suddenly mentioned something he had forgotten, whereupon the fat cat got ticked off and ruthlessly started to abuse him.