A few werewolf girls (a relatively light one, an average one and a heavy one) lined up in casual dress. I did this to help give an impression of how they dress.

-Stealth suit
Werewolves aren't "toons" (ie anatomically incorrect). They still have privates that need to be covered up. However, because they are covered in fur, it's not always practical for werewolves to wear clothes that cover their whole bodies, and it's never been considered by werewolves taboo to wear minimal clothing, as long as the naughty bits don't show
As a result, werewolves often wear stealth suits, bikinis/speedos which blend in with their bodies while keeping them decent. They are often made from the werewolf's own fur. They are comfortable, easy to wear and don't interfere with the werewolf's movement.
Because they take some effort to make, girls with "gaining issues" often have to wear simple swimsuits.

-Swimsuit
Does same job as the Stealth bikini, for girls who can't stop gaining weight.
Males normally do not wear similar, if they don't wear stealth suits, they're happy to wear shorts (they have more freedom with pants because legs and bottoms aren't fat like females')

-Human clothes.
Whether they're ex-humans still adapting to werewolf ways or werewolves making a fashion statement, human clothes are often worn. Pants are common, even though they have trouble containing a girl werewolf's body. Jackets and coats are popular even for those wolves that don't dress up. Many ex-human werewolves try to cover their bellies but they have to end up accepting bare midriffs from themselves.
Many werewolves purposely buy clothes that are too tight to emphasize their bulk.
The werewolf pictured on the right is a kind of punk/tomboy, and they tend to eat more and take up more space to appear more aggressive.