Got it! Body paint. Or better yet, tattooed clothing! Just as an emergency fallback, for those times when you absolutely, positively, must tear off your duds and can't get new ones (and Lycandex® is unavailable). It wouldn't show under the fur, or under actual clothing. Maybe a thong or posing pouch to cradle the junk (and as a modern-day fig leaf for those PG rated moments)—slitted to allow for tail growth of course. Otherwise, rely on keeping a few changes of clothing in the car, maybe a backpack or duffel bag you can carry for bug-outs for that next level resort. Everybody carries extra, and sized large so if any of their friends need a clothing fix, voila!
So it feels like I have very, very few options open to me, and that almost any of them will feel dumb in some way.
Here's another option—fight naked in wolf form, then kill passersby for their clothes. Yeah, honestly I think the options are pretty limited. One crazy idea that occurred to me—small thin backpacks worn under clothes that sort of unzip or unfold to become emergency clothing. The packs would stay on while in wolf form. But I mean, that just wouldn't look right.
What if they just all like to wear wool? Because that would make them the proverbial wolf in sheep's clothing. OK, I'll get my jacket now.
Here's my take on this. Yes, in some situations they'd need to strip down fast for a fight. Those are crisis moments, when they need to revert to pure savagery. And yet you seem to want them to also be totally prepared to put their clothes back on, or something similar, as if nothing happened—all unruffled. To me that doesn't feel dramatically appropriate. In fact if they can do that, it makes it seem less powerful. When you transform into something primordial and engage in fang and claw warfare, you shouldn't be able to just dust yourself off and adjust your cufflinks afterwards (damn, get out of my head Travolta! You too BeeGees!) Maybe after that kind of melee they should have to scramble naked bloody and wounded, disperse and regroup however they can. Some might get arrested for indecency (would the police be able to arrest them?) and for, I don't know—suspicion of malfeasance or something?? Maybe take this difficulty into the story—have them constantly trying to solve the same problem you're struggling with. They keep making various forms of break-away clothing. Maybe different ones try to solve it each in their own way.
EDIT—just checked the OP. They get bigger, Twilight-style. Disregard the rest of this post please. My other thought—do they turn into normal sized wolves? Do they get bigger, as in Twilight? Do they become a wolf/human hybrid like in The Wolfman or The Howling? This determines a lot for your question here. If they become normal wolves, those are smaller than humans and clothing wouldn't tear off Hulk style, but would become an encumbrance if they didn't remove it before transforming.
I mean part of the fun of being a werewolf is ripping those clothes off after transformation and embracing your feral side. What they could do is carry a bag of clothes on their back while in werewolf form then once its over quickly dress up.
Slept on it for a bit and woke with this. You said the clothes don't transform, and by that you mean they don't change shape and size while remaining clothing. But there are other possibilities we haven't begun to touch on, because we're accepting the standard werewolf cliche of watching the transformation occur. You know, the body re-shaping itself and hair growing etc. But right there, you've got an unexamined werewolf cliche just waiting (begging) to be exploded. And isn't it our jobs, as writers, to root out and desecrate cliches wherever we find them? How about instead of the rapid reshaping of the human body into wolf form, there's just a quick blurring, a visual swirl, and presto-change-o, where stood a man now crouches a wolf-thing. Clothing and jewelry absorbed at a molecular level into the body, to become exactly what it was in the switch-back. Or maybe it all falls off into a little pile at their feet. Or just vanishes entire, then re-appears magically, and in appropriately PG-rated form, on re-humaning. Or something even wilder. I know my subconscious mind had a hand in this, because as I was falling back asleep (I woke @ 5 am and wrote my earlier pair of entries) I had a brief dreamlet showing a bunch of banana pepper slices swirling inside a jar of liquid, changing form as if becoming werewolves.
This one got me thinking. What if the transformation into wolf form at some point just makes them incorporeal briefly, so their clothes fall off without being ripped, and they re-manifest in wolf form shortly after? The only issue is to add some sort of... I dunno, theme or point to it so it doesn't seem specifically cynically designed to allow them to transform quickly without stripping first.
Some strippers wear clothes with Velcro fastenings so that they can pull them off instantly while dancing. I imagine that would work well for a werewolf: the change causes the velcro to separate (or the wearer rips them off), but the clothes are unharmed and available to wear again once they return to human form. Long hair seems common with female werewolves in TV and film because it allows their breasts to be covered while they are naked, so that might be worth considering if you're hoping for an adaptation. On the question of wifwolf or wyfwolf, I suggest being careful. People are used to werewolf being used for both men and women (oddly, I can't remember ever seeing a child werewolf, so maybe that's a newish twist you could add). Most people won't know about the old meanings of wer and wyf, so might be confused about wyfwolves and wonder if they're a different kind of supernatural creature.
There was Eddie Munster: But I don't think we ever saw him in wolf form, and to me he always looked more like a little Dracula.
Well the idea is more that each race has an equivalent word of "man", "woman" and "human". In this case it's werewolf, wifwolf and lycan. The plan at the moment is to have such vocabulary for every species of immortal. For example, male vampires are moroi, and female vampires are moroica. How long have those been a thing, and how obvious is it to the casual observer that something's off with it?
OK, but "werewolf" already is the modern day equivalent of "human" to most people's ears, so maybe you're better off calling the males "manwolves" or something similar. Interestingly, in Old English, where "wer" meant "man" and "wyf" meant "woman", the term for "human" was "man", which suggests that "manwolves" would be an equivalent for "human", but your readers are going to associate "man" with its modern meaning. I don't know. Velcro wasn't manufactured commercially until the late '50s though. I think they're pretty good looking to a casual observer, and there's no reason they can't have fake buttons or zips on them to look even more realistic.
Like Tang and Moon Boots and the new heat-reflecting synthetic fabrics etc, it was an offshoot of the space program. And, like Moon Boots, apparently custom designed so the nerdy kid (whose mom bought him the fancy new nylon-covered binder to carry all his school supplies in) can get laughed at when he goes to open it in a totally silent classroom where everybody is using their Number 2 pencils to fill in the little circles on the standardized test form. Suddenly that unbelievably loud ripping sound echoes all around the room, and in his embarrassment said nerd, having accidentally let the binder pull itself closed, must once again draw all attention to himself as even the teacher now laughs uncontrollably. Not that I ever experienced that or anything.
You That nerdy kid can stop blaming the space race for that: http://www.todayifoundout.com/index.php/2012/04/velcro-was-not-invented-by-nasa-for-the-space-program/ Turns out that nature was responsible for Velcro: https://www.thoughtco.com/the-invention-of-velcro-4066111#:~:text=Velcro%20was%20the%20creation%20of%20Swiss%20engineer%20Georges,to%20his%20pants%20and%20to%20his%20dog%27s%20fur. That last link contains this great quote: "Because Velcro can be too noisy in a combat setting ... it has been temporarily removed from military uniforms." So you weren't the only person to have a problem with Velcro's noise. It makes me wonder if people have died as a result of it. If the OP goes with werewolves in stripper clothes, then this sounds like something worth building in at some part of the story.
Now THAT is a great quote!! I can see them tearing away the frilly corsets and G-strings, with a big boom box on the ground nearby cranking Girls Girls Girls and Cherry Pie and Pour Some Sugar on Me. I can foresee certain problems with magnets as well. If you get one reversed, they don't attract but repel, very powerfully if we're talking rare earth magnets. I can see people disoriented after a big fight struggling with clothing and the front of a shirt is pushing powerfully away from the back part. Of course a smart designer would use one magnet and a little piece of steel for each pair, that way no possibility of repulsion (but that also wouldn't allow for as much dramatic fun in the story). You might also find small metal objects hanging from your clothes at the end of a day. Also, good to know about Velcro, thanks @Storysmith . I just accepted the commonly believed story. Hey, at the time there was no internet to check on things like that! We just heard it on the news and believed most of it.
Magnetic clothing fasteners do exist, but they can prove fatal too in other ways, especially if your book isn't set in the present or near past: https://www.theguardian.com/world/2018/feb/15/magnets-clothing-compasses-fail-walkers-warned That would make a memorable book title.
I don't think the magnets in the clothes would be that strong. The issue there is that I don't think those would naturally come apart from the force of the person wearing them rapidly getting bigger. That would be a sideways force as the fabric is pulled tight. That's the thing with magnets, they don't really care whether you pull out or pull to the sides, it'll still pull the magnets apart regardless.
That's an exaggeration, of course. Yet, the effect depends on the distance between the magnet and the metal object. I remember leaving a magnetic lapel pin on a door once. So, weak magnets will work for the car example (except for getting in and out), but they probably won't save lycans from odd accidents during the day. As for snaps, they can be rather loose, and you actually can adjust their tightness with a screwdriver and a pair of pliers. There are also the plastic ones they use on baby clothes - they're lightweight and very easy to open even if the fabric is pulled to the sides.