My method was “look at your fingers”. It’s easy, cause they are familiar and often in sight by default. I remember first time raising my hands and seeing that.
I imagine it would be even more shocking when noticed, but possibly easier to go unnoticed - since visually, morphing is continuous in dreams, but word meanings are discrete and can't morph into one another like that.
Btw. funny (and fascinating) how "dream-rendering" has similar issues with producing realistic hands as LLMs. Similar with continuity issues.