You pissed off a witch.

Sometimes it runs in families for generations, sometimes it takes a girl months to figure out what's going on.
Sometimes it's a harmless bit of fun untying your bikini while you're tanning in the yard, Sometimes it strips you naked at a crowded beach with a single wave.
Maybe it's a right of passage that happens once with a bang or maybe it has a trigger like thinking or saying something. Maybe the trigger is situational or tied to an emotion.

Less powerful magicians are known to harness the wind to pull at women's clothing at opportune moments.

While more powerful curses of embarrassment have been known to completely vanish or otherwise make clothing completely transparent without it actually leaving the body.
Generally these spells come with a certain level of lowered inhibitions, but they are very much will based. If someone truly wants to be clothed and modest with the entirety of their willpower the magic will have severely less or even no effect. However if someone has desires to be seen and even worshiped, no matter how well hidden they may be... Some are easier to curse than others.