To edit the text in an image and rearrange the letters to spell a nonsensical and often sexually suggestive/explicit phrase. Similar to the recurring gag that appears in the children’s book series “Captain Underpants”, but more risqué. The original “Expand Dong” was morphed from text found on the box cover of Donkey Kong 64.
sbubby is a variant of Expand Dong that focuses on corporate logos.
That “ThiccMints” image is one of the best examples of expand dong that I’ve ever seen.