In the second and third lines of the poem, the speaker invites somebody, namely "the roller of big cigars," to "whip / In kitchen cups concupiscent curds." There are a few unusual or uncommon words in this quotation, and so it is probably best to begin by tackling those words.
First, let's consider the word concupiscent. This word is an adjective, and it is used to describe someone or something which is full of sexual desire. A person or a dream might be described as concupiscent. Curd is a noun, and it refers to a substance formed when milk coagulates. Coagulation is the process whereby a liquid is turned into a solid or semi-solid state. Curd is what milk is called when that milk has been coagulated into a semi-solid state, not dissimilar to yogurt. One can turn milk into curd by bringing the milk to a low boil and then letting it simmer for about fifteen minutes. If one then whips the curd, with a whisk for example, the curd will become lighter and smoother.
If we now return to the original quotation, we can determine that the speaker is asking somebody to make some curd and then pour it into some cups, and then to whip the curd until it becomes light and smooth and so even more delicious. The word concupiscent is used to exaggerate the deliciousness of the curd, implying that the curd will be so delicious as to inspire an almost sexual lust in anybody lucky enough to eat it.