Here are some options, depending on what you're looking for:
* Near rhymes:
* squished crap: This is a very informal and potentially offensive rhyme.
* squished flap: This is a less offensive option but doesn't quite fit the meaning of "cap."
* Eye rhymes:
* squished map: This has the same spelling at the end, but doesn't actually rhyme.
* Creative options:
* You could use a made-up word that rhymes with "cap," such as "squished sap" or "squished slap."
Ultimately, the best rhyme depends on the context and what you want to achieve.