Dear Mr. Onion,
Have you asked yourself why you're having trouble generating an ending here?
I think that you may be having difficulty because you haven't thought about what gives people the feeling of ending.
There are different kinds of feelings of ending that seem to depend on the internal pattern of playfulness that the poem is using. It's useful to look at poems you gain a sense of strong enjoyment from reading with an eye toward what the pattern of play may be that makes them work.
The pattern I think you are looking for here may be something like
1) an initial stanza which sets out a particular form of patterned rhetorical statement. You've chosen a series of
single-lined noun/verb statements, a particular metrical scheme for the progression of the lines, and a rhyme in lines two and four.
2) A second stanza, to get the sort of effect you want here and to develop a sense of ending should parallel the first. It too should be a series of single-lined noun-verb statements, it should follow the same metrical scheme, and the rhyme in lines two and four should continue.
The reason for doing this is to establish as an element of play that the pattern that you established in the first stanza is not accidental and for the reader's nervous system to get used to the pattern you've established.
Some poems continue this part of the pattern for a number of stanzas by introducing elements of development in the stanzas, perhaps by indicating a progression of time, perhaps by indicating progression through some sort of list as you are doing in this case. If the poet opts for this sort of situation, it works better if the progression is orderly to preserve the sense of pattern that the reader is developing for the poem.
3) At some juncture, where the poet wants to start to develop toward an ending, he or she throws in a variation in the sense of parallelism of the stanzas. Perhaps an inversion of noun-verb to verb-noun structures. Perhaps the use of a compound sentence along with a variation in the sort of statement and meaning the poet have been making within the stanza. This works as the announcement of a playful variation on the original theme that is reflected in a playful variation in the form of the stanza. It indicates to the reader that the end or the clincher is coming up.
Because you haven't thought about doing this on a structural level in your poem, it's difficult for you to imagine bringing your poem to a close.
You also haven't made a commitment to keeping the second stanza in clear parallel with the first, beyond the meter and the rhyme. Neither you nor your reader have been given a chance to build up an expectation for what should be coming in that third stanza (either more of the second stanza with some sort of development or a variation and twist).
4) The fourth stanza or the fourth part of the development should be the return to the original form or stanza without the variation involved in the third stanza but with an announcement of how things are now different in the world of the poem because of the variation you introduced in the third stanza. This gives a maximum sense of ending and is the pattern I think you're looking for here.
The guy who is an absolute master at pulling this sort of thing off is A. E. Houseman. You should find some examples of his stuff on the web without much trouble at all and see how he makes it work. Once you get a sense of what he's doing, it should be simpler for you. I hope.
Let me know if it's helpful, anyway. BobK.