Source:
https://scmp.com/magazines/hk-magazine/article/2037586/no-cream HK Magazine
No Cream
吹水 (chui sui), v. Cantonese slang. To chat, bullshit.
"You are being unreasonable."
A pun on the term mo lei yau, "no reason," and the similar sounding naai yau, which means "condensed milk" in a cha chaan teng.