Look at the individual words you have written. What are their opposites?
Choose one of the words that is the opposite of some word in the sentence you wrote. Use that word in the second sentence, however you happen to write that sentence.
Your third sentence will include a word that is the opposite of one of the words in the second sentence.
And so on.
Continue writing sentences and at the same time, continue a chain of opposites, all the way down the page.
Resist the idea that you are supposed to “make sense.” Focus on the possibilities of opposite-words and listen to the sentences that pop into your mind.
When you have finished, reread your work. Make small changes if you want to. Add color or illustration, and a title, too. Put your initials and the date somewhere on the page.