As you've probably already noticed, "The Emperor of Ice-Cream" is not a poem that's wallowing in tears, even if it's set at a wake. Instead, it's got a carefree sound to it that's not holding us to any one dominant form, meter, or sound pattern.
Still, we can spot an instance or two of alliteration or the repetition of initial consonant sounds ("cups concupiscent curds"), and assonance, which is the repetition of vowel sounds (like the short I sound in "bid him whip"). What is this doing in the poem? Well, consider the joy of language play, for example with a tongue-twister or a good old onomatopoeia. There's just something really enjoyable about playing around with sounds in language, isn't there? And here, in a poem that's asking us to embrace such a moment of enjoyment, we get this kind of sonic play. It's like Stevens is serving up some ice cream for our ears!
There are other sounds to pay attention to, as well. The rhyming couplets that we get at the end of each stanza have a fun sound to them as well. Each word, "seem" and "beam," rhymes with "ice-cream." Not only does this focus our attention more on the importance of the symbolic ice cream (see the "Symbolism" section for more on that) and the words that surround it, but it also reminds us that we should be enjoying the sound of the poem as well. For, if we are, then that kind of in-the-moment fun is keeping us from the meaningless distraction of appearances, and the speaker's message has sunk in!