Christopher Doyle's cameo character Jeremy in "Tian mi mi" has a nickname "Chai Lou Mei" (literally: vegetarian stewed dish). He appears in "McDull, the Alumni" as well, playing the owner of a eating house whose employee recommends the dish "Chai Lou Mei".
The way the Morse code is used in "Mou gaan dou" (transmitted by tapping a finger) is spoofed in "McDull, the Alumni" (transmitted by shaking spectacles).