"O here here how hoth sprowled met the duskt the father of fornicationists but, (O my shining stars and body!) how hath fanespanned most high heaven the skysign of soft advertisement!"
The Wake refers to the entirety of itself in nearly every sentence so, in many ways, the bit you quote is about everything, everywhere all at once. It's also written in nearly every language simultaneously with multiple allusions to all of western literature, a great deal of eastern literature and pretty much every mythological tradition. Any praise of it from me would be entirely superfluous. Nothing like it can ever be written again.
It's probably helpful, then, to try and situate the sentence you quote a bit. The Wake is roughly mapped to the Italian philosopher Giambattista Vico's cyclic view of "cultural" history. For example, the last words in the "book," "A way a lone a last a loved a long the," run on to join the first words "rivverun, past Eve and Adam's." The "commodius vicus of recirculation" (from the opening page) is both an allusion to this cyclic form ("Vicus (Vico) of recirculation") and a humorously self-deprecating reference to the Wake's as a "load of shit" (commode) filled with recycled quotes ("recirculation") which one must plough trough.
The passage you quote occurs very early on, when Joyce speaks of The Fall. The "fall" is many things, both miniscule and cosmic. It is Adam & Eve's eating from the tree of knowledge ("When he yeat ye abblokooken" (When he eats the cooking apple (forbidden fruit), with abblokooen reminding also of the German word Apfelkuchen, meaning apple pie - with also a further allusion to the poet Yeats, who, due to his revivalist sensibilities, Joyce regarded as being (to paraphrase) “beyond help” when they met.) "The fall" - "Bababadalgharaghtakamminarronnkonnbronntonnerronntuonnthunntrovarrhounawnskawntoohoohoordenenthurnukis" (which depicts the word "thunder" in many different languages) - is also the fall into language, and the fall of Irish political leader ("The Uncrowned King of Ireland") Charles Stuart Parnell, who so nearly achieved Home Rule before being undone by an affair with a woman called Kitty O Shea. It is, therefore, also the fall of Ireland. It is the fall of humpty dumpty ("That humptyhillhead of humself prumptly sends an unquiring one well to the west in quest of his tumptytumtoes). It is the fall into divisions and conflicts. And (as I will try to argue in my Ph.D thesis), it is the Heideggerian "fall" into-being, as
dasein. It is also the fall of the main character(s) in the book, H.C.E., both man (Humphrey Chimpden Earwicker - chimpden perhaps is an allusion to Darwin) and men (Here Comes Everybody). H.C.E man/men also represents the earth: "Howth Castle and Environs," just as his wife, A.L.P. - Anna Livia Plurabelle - represents the river. H.C.E. is embroiled (“fallen”
in some kind of sexual scandal with his daughter, though the details are never made explicit.
To look at the specific passage you quote:
"O here here" should be seen in context with the previous lines, which detail numerous "falls" and conflicts of man from the specific to the grandiose. The passage is a litany of falleness. Our location is revealed in the previous paragraph "Where oranges have been laid to rust upon the green" (The colours of the Irish flag), though it is, of course, everywhere as well as Ireland. "Here here" is a vocal expression given by MPs in parliament to pledge support to a cause (possible connotations to the case of Parnell, who was leader of the Home Rule League). It is also, of course, an invitation to listen.
"how hoth sprowled met the duskt the father of fornicationists"
"How Hoth" is "Howth," is Howth Castle, north of Dublin, is H.C.E. is man, is men. "Sprowled" is sprawled - flung out of Eden, denied home rule, lost in language - and "prowled," like a beast & reminding of Earwicker's sexual scandal. "Met the duskt" is both "dust" and "dusk," with Finnegans Wake being a dream, an other, a "book of the night" to set against Ulysses' day. The snake in Eden was forced to crawl on his belly in the dust. The father of fornicationists is both Adam and Earwicker. The passage is brilliantly suggestive of an "Other" "duskt" of subconscious sexual desire, and also an "Other" of language, which undoes attempts to master it in the writing, with Freudian slips and destabilising deconstructions. Also, language is the house of Being. "Man acts as though he were the master of language, while in fact language remains the master of man" - Martin Heidegger
"but, (O my shining stars and body!) how hath fanespanned most high heaven the skysign of soft advertisement!"
"O my shining stars and body!" is a possible allusion to Christ and America, with "stars and stripes (Christ's scars)" reminding of the previous "Laurens County's gorgios doublin their mumper" (referencing there being another Dublin (doubled!) in Laruens County Georgia ("mumper" is Irish slang for "father" - "Topsawyer's rocks" are shamrocks and also an illusion to Tom Sawyer, whose "father" was Mark Twain (twain meaning split in two: doubling!) "My stars" was an Irish vernacular phrase.
"How hath fanespanned most high heaven" is very interesting. How hath is Howth (H.C.E.) castle. "Fanespanned" suggests "fane" (a flag or weathercock). So: "how Howth Castle flew its flag." But also, from the Bible, in Isaish we have "my right hand hath spanned the heavens," which is of course Joyce writing the Wake, and also an allusion to masturbation, with the pun on "weathercock." (The date of Ulysses marked the first time Joyce was given a hand-job without paying for it by his wife-to-be Nora Barnacle!) Creation then is God's hand-job. The Sistine chapel ceiling was also "spanned" by a hand, but Michelangelo was left-handed.
Finally, "the skysign of soft advertisement," refers to the weathervane of man's fall. The weathercock "advertises" the climate of life. The "ontological weather," if you like, of his state: angst. It also might refer to Spinoza's (much beloved of L. Bloom) pantheism, with the sky itself suggesting God by way of advertisement. It also might return to American culture and "soft advertisment" (soft drinks advertisments) to go with the "stars and body (stripes)" of the first part of the line. A flaccid penis is “A soft advertisement” of possible pleasures to come – at the very "beginning" of the Wake we are “before” the fall (into intercourse/sexuality?) (“had passencore rearrived” (pas encore, in French.)
I hope the above is somewhat helpful. I think it's rather crude to try and "translate" the Wake but I fear there is no tasteful way to write about it on an internet message board. There is likely much I've missed. The Wake is important because it moves towards a new way of thinking. Towards, as I will try to argue in my doctoral thesis, a "being-historical" awareness in which all cultures and mythology are disclosed and renewed authentically from within “language,” free from the drift of ideology, “revivalism” or studied "history."