1. S1-4 are in the past tense and S5-6 are in the present tense. To avoid confusion, I would put the whole poem in the past tense.
2. I would make S1L1-2 and S1L3-4 separate sentences. Currently, S1L1-4 are a run-on sentence.
3. The end rhyme of S1L3 and S1L4 is “lacked words/backwards.” I would try to change the end rhyme to “lack words/backwords,” and would also smooth out the trimeter in S1L4. Here is one idea:
The problem was not that the fellow would lack words,
but he was compelled to assemble them backwords.
4. In S2L2, I would move the comma from after “so” to before.
5. In S2L4, to smooth the trimeter, I would change “fully” to a one-syllable word (such as “more”).
6. In S3L4, I like the assonance (felt… welcome).
7. I would make S4L1 a separate sentence.
8. In S4L2, I would put a comma after the second “practiced.”
9. I note that S4L3 has a feminine ending and S4L4 does not. I would try to make the meter of these two lines match. You could give the second line a feminine ending. For example:
as once more he blurted: “Kiss a me give you will?”
His overture ended up uninfluential.
10. I asked my wife to read the poem. Her comment was: How could he possibly see that the girl was “petrified” and conclude that “her reaction is cool”?
11. I would want the final two lines (the punch line) to have perfect trimeter. Something like:
The smile was constrained and the words uttered slow.
From the lips of his angel came: “Yourself fuck go.”
12. The poem is fresh, inventive, entertaining, well written, and fun. I see no reason to shorten it.