Try as I might, there was just no way around it: this boring-as-shit chapter was integral to the plot. I had to write it. So how the hell do I make it interesting?
Why Does It Even Matter?
'Get to it and shut up. You're a writer, this is your job.'
Yeah, it is. But the thing is, what's boring for me to write is boring for you to read. This is true of all genres, but especially for erotic fiction (everything pops with a little more passion in erotica). So when I'm happy, you're happy. If I'm not, you'll go elsewhere to get your fantastical kicks. Which is totally understandable, cuz why the hell would you settle for crap writing anyway? Even "free" stuff costs time, and you could be spending it doing something that doesn't suck.
So, yes, it does matter. Figuring out how to make it interesting to write settles the problem of making it interesting for you to read.
Ok, So Then HOW?
'Quit jerkin' the chain and get to the meat. Ain't got all damn day.'
So I did some research, and there's a few decent suggestions. I went with a change of perspective, which I'm gonna call the "George R.R. Martin' technique (nobody evokes provocative confusion the way he does), but there's plenty of other tactics that may be of note below.
Cut It Out: Really ask if the scene is necessary. Is there another way to present the information, an alternative solution to the plot, or a different action the character can take? By the time you're wondering how to write a scene better, you've likely already determined it's necessary. However, just in case, this is the time to think about chucking it entirely.
The Big "D": Develop the characters. If you must have a dull scene (sometimes the pace has to slow way the fuck down), let the character spice it up for the reader by introducing some of the personal stuff. Drift off to a steamy memory, play a body parts word association game, or let a conversation get... weird. Introduce a little depth to the characters involved, and even mundane moments can be interesting to read.
Troll For Action: It's time to put your 'God-cap' on and think up minor inconveniences that could befall your character here. Or maybe you have something already, but you could play up the melodrama a bit more before it's too emo. The rule of writing flow is the slower the pace, the more closely we can examine emotions. So maybe this is a good time to make a mountain out of a molehill, or drop a broken bra strap into the mix just for funsies.
Cloak The Truth: If you've got to say something, and it's boring to say, then don't say it directly. Find ways to reveal the boring exposition and grinding go-betweens in ways that don't get directly to the point. It's not really lying, so much as it is being circuitous. And if you're thinking this seems like a bunch of literary foreplay, you're not wrong.
Fantasize: So, you know how sometimes this huge, unexpected, amazing thing suddenly comes crashing in and makes everything super-cool and awesome? This is like that, except that it technically never really happens. Let your character (or yourself) fantasize about what could happen in this scene, if things were just a little different. Imagine everyone naked, or being totally uncharacteristically horny. Whatever the fantasy, make sure to come back for the great disappointment of it NOT actually happening (unless it works with the plot to keep it!).
Perspective: If the book is in third person, and you've either been following one character so far and introducing another (which technically makes it third person limited), or have third person omniscient perspective already, maybe it's time for a perspective shift. Look at your sexy main character through the eyes of someone new for a change of scenery. This can really fuck with the reader's point of view (being perspective and all), so take care when using this tactic.
Introduce Mystery: Find a question, any question. The reader reads to find answers to their internal questions about what will happen next, but you can insert your own compelling, nagging questions too. Like, will this scene secretly be the moment the character has some huge revelation about their sexuality or discovers a pivotal plot element unlocking a potential threesome? You know it's not, but they don't. Sometimes you gotta get the reader's hopes up.
Why?: Whatever is happening in this boring-ass scene, ask yourself 'why?' Why are they clothed, why are they sitting, standing, laying, etc? Every little choice can be an opportunity for that development gold discussed earlier, so make sure you're milking it in moments like this.
Find The Devil: In those incessant details. 'Why' scratches the surface, but there's all kinds of other considerations. Is there music? Any ambient sounds, smells, annoying light reflections, temperature discomforts, or otherwise ignorable content you've neglected? Have you drawn up a rough map of the scene to know exactly where every twist, light, item and being is located each step of the way? For some slow scenes, incredible, painstaking detail keeps things fresh.
As You Were
I'm sure there's more (and as I come across them, I'll add them here), but this is a good start. There's enough ideas here to get those blocked gears turning, and that's really all you need anyway. That's all these 'tactics' are, anyway - methods to help get your mind going again. Every writer knows the crushing pain of writer's block, and I don't think you can have too many ways to get you unstuck from it!
If these suggestions don't get you out of that boring scene bind, then let me know. I'm always looking to improve my skills (or prove my point). Comment below and we'll try to get you sorted! Even better: if you've come up with a tactic you'd like to add, let me know that too!