It is a mystical thing found in the ass of a man Very few have found it. To find said onnommonopia you have to travel about 4-5 inches in the mans ass there you will find riches.
Her: Let me search for your onomonopia tonight I didn't win the lottery.
Him: Never again your dildo is too wide.
When the pronounciation of a word sounds similar to the noise the word describes.
Sizzle sounds like the noise something makes when it sizzles, and is therefore an onomotopaeia. Other examples of this would be words like ding, moan, or chirp.