It can never be opposite day. When ever you say "HEY IT'S OPPOSITE DAY!" the opposite would apply therefor it would not be opposite day. Also if you say "IT'S NOT OPPOSITE DAY!" the affect is not applied.
Down where it's wetter 🌊 Take it from 🦀me 😍 Up
on the 🏖 shore they 👔work all day😅 Out in the 🌞sun they slave away 💦While we devotin' 🐠 Full time to floatin 🏊🏽 🎵Under the sea🎵