Composition classes have been lauding the short sentence for
about 80 years. I’m not going to tell you the short, sweet and tight is bad; it
isn’t. I love it, often employing a consciously clipped style myself. It’s
effective for the gritty, brutal narrative and it affords a great deal of space
for the reader to root around it.

It’s been Hemingway vs Faulkner in the world series of
wordsmithery forever  but, if you do
a little investigation, you’ll find that Hemingway wrote some very long
sentences and Faulkner wrote some very pithy short ones. That’s probably why, even
after all this time, they’re still considered paragons of literary style.
Because, although they are each known for their radically different sentence
constructions, they both knew when to switch gears and break out of their own
stylistic niche to good effect.

Just the facts, ma’am and no purple prose. The popularity of
the short, sweet sentence arose with the emergence of the journalistic style,
evolving the way it did, partly due to technological limitations and partly for
clarity. When news stories were first transmitted by telegraph, there was a lot
of drop-out on the lines. The shorter the sentence, the less likely it would be
cut off. Hence the inverted pyramid format. And, hard as it is to believe now,
literacy was still relatively low at the dawn of the 20th Century. The press
was part of a democratization of information – particularly in the US – and
that effort included writing in plain, simple language.

Now it’s simply a matter of acclimatization to style. In
genres that place an emphasis on hard and gritty, you see the preference for
short sentences and unadorned language. Thrillers, horror, hard crime fiction
and any other genre that relies heavily on action tend to preference the short
and sweet. Unless the writer is very skilled, too many sub-clauses can gum up
the tension and slow down the pace. But allow me offer you an alternative.
Here, from the master of the short sentence, is a long one, pure action, with
all the tension and fluidity you could ever hope for:

George was coming down in the telemark position, kneeling,
one leg forward and bent, the other trailing, his sticks hanging like some
insect’s thin legs, kicking up puffs of snow, and finally the whole kneeling,
trailing figure coming around in a beautiful right curve, crouching, the legs
shot forward and back, the body leaning out against the swing, the sticks
accenting the curve like points of light, all in a wild cloud of snow.

Yup, that was Hemingway with a 75 word sentence.  Did the sub-clauses slow it down?

There is a place for short, staccato sentences in erotic
fiction, but when I encounter erotic writing devoid of any long sentences, I
find it effective but not affective. My intellect engages, but my emotions and
my senses don’t. Lots of erotica leaves me not very high and literally bone
dry. Writing style is often the prime culprit.

Long sentences with a kernel or root clause and subsequent
sub-clauses that elaborate on the main one are a way to pull the reader into
the moment affectively. They offer substance, direction, rhythm and texture,
engaging the emotions, the senses and the reader’s ear. It complicates ‘the
facts’ with the meat of human experience; it offers shades of meaning to what
is happening in the story.

For those of you went to school after they stopped teaching
grammar, the kernel or root clause is the main subject, very and object of the
sentence.

Tracy adores cunnilingus.

 Now we’ll add on a sub-clause:

Tracy adores cunnilingus, since it’s the only way she can
orgasm.

Now a one more:

Tracy adores cunnilingus, since it’s the only way she can
orgasm, regardless of her lover’s technique in other areas.

We’ve put significantly more substance in the sentence, and
you’ll notice, there’s also a direction. 
We start out with the root clause ‘Tracy adores cunnilingus’ and then we
are elaborating by adding modifiers after that statement. But we could easily, perhaps
more elegantly, shift things around and add a little more:

Regardless of her lover’s technique in other areas, Tracy
adores cunnilingus, whining for it like a persistent cat in heat, tugging on his hair to drag his face down to her cunt, since it’s the only way she can orgasm.

The problem with long sentences is that there are a lot of
words in them to misuse. Run-on sentences are often painful because they’re
poorly constructed. The reader loses her grasp on the kernel clause, even on
the subject itself, and can’t remember what all this modification was actually
modifying. But, as you can see above, we haven’t lost the plot. This is still about Tracy’s love of a good licking.

Well written long sentences should enhance the reader’s
depth of understanding of the subject, not lose it. The addition of sub-clauses, either
free modifiers or bound ones, should deepen the in-the-moment ‘thereness’ of
the reader instead of jerking him out of the narrative in a tizzy of
‘lost-the-plotness.’

No matter what composition teachers tell you, language is
not like mathematics. In mathematics, elegance is based on simplicity and
compactness, but language is an additive beast. The more details you get, the
more you know.  I’m not saying that
the mot juste is not important. But
when language gets too clean, too pithy, too simple, it can lose its humanity.
It can also lose its rhythm.

This is particularly true when it comes to writing sex
scenes with a view to arousing the reader. Literary fiction writers will often
stick to a description of the mechanics in a sex scene. It’s about as sexy as
jumping jacks or watching dogs fuck. The whole thing is rendered like a series of
short, sharp stabs. All showing and no telling. If they’re scared of being
accused of purple prose at any time, they’re terrified of being accused of it
during a sex scene.

But erotica writers know better. When you write a good sex
scene, you fuck the reader. And good erotic fiction writers are, at least
mentally, accomplished lovers. They vary the pace by varying the length of
their sentences. They vary the sensory experience by glancing the subject in
some sentences and going in for the hard and deep plunder in others. They’re
not under the illusion that a ripped body and a 8″ cock used artlessly is going
to ever compete with the delicious rollercoaster ride of a well-executed
mindfuck. A hot quickie is pleasant, but a good erotic literary mindfuck is a
memorable thing. It requires that you make ingress into the reader’s affective
mind, not just their imagination of the narrative physical event.

The chief problem with long sentences is that people feel
they need to use prepositions and pronouns. If they don’t bind all those
sub-clauses together, it won’t be logical.  So, you get this:

 He
pressed his open mouth over her left breast, then stroked the tip of his
searing tongue around her nipple in a circular fashion before sucking the
entire area into his mouth, afterwards leaving the indentation of his teeth
behind on her skin.

Admit it, you felt the need to take a deep breath,
right?  It’s cludgy. When possible it’s better to set your modifiers free (bound modifiers attach to the sentence using joining words or prepositions, free modifiers don’t use them).

You need to trust that your reader is smart and with you.
They understand that the progression of words is the progression of events, and
they know enough about anatomy and how tit sucking works not to need half that
crap. You’ve already established who is doing what to whom, so you can be a little less concerned with locating everything in time and space.

 Pressing an open mouth to her breast, he circled her nipple with a
searing tongue and, sucking hard, marked her skin with his teeth.

You can’t get rid of every pronoun or every preposition, but
you really don’t need most of them. 
Although a good deal shorter, it’s still 25 words long . Not exactly short. I admit to having written much longer
sentences and I could easily slow down the pace and be languid in my
description of this, using more adjectives, an adverb or two if needed. It
depends on how I want the reader to experience this particular piece of intimacy.

Sentence length should be about depth of knowledge, direction, pace and rhythm.
Just as there is a place for the short, hot, meaningless fuck, there’s a place
for the long, slow, pulsating, eviscerating annihilation of the flesh and mind. And your ability to execute either of these
depends on your ability to be flexible in the way you construct your sentences.

If you’re up for it, there is rather deeper examination of the topic of sentences and especially of modifying sub-clauses written by Frances Christensen. “A Generative Rhetoric of the Sentence” linked here. It’s a pdf file.