What Leo is doing is using the sound " schm" (schm), which is very common in Yiddish words, and attaching it to English to create a word to be funny, to make a word sound like as if it were Yiddish.
Leo 所做的是利用意第绪语单词中很常见的发音“schm”（施姆），并将其附加到英语中， 创造一个有趣的词，让一个词听起来像意第绪语。