Forget about rainbow hair on your head -- the latest place to dye is the armpit.

The trend for technicolor underarms has been growing slowly but surely for a while, but was brought into the spotlight last week by pop singer Miley Cyrus. The star posted a picture to her Instagram account showing her wearing a white crop top, rolled down jeans and layers of beaded necklaces. However, she had accessorized the outfit with bright pink body fuzz, and wrote the caption "#PANK #dirtyhippie" alongside the photo.

One woman who knows all about the trend is US stylist Roxie Hunt, who dyed her co-worker's pits bright blue and then wrote a blog post about the topic which has attracted over 35,000 views.

"More and more often, I am meeting women who unapologetically choose not to succumb to the societal pressure of scraping a razor against the soft skin of their bodies," writes Hunt. "If you recall, I want to celebrate pit hair."

The process involves first bleaching the hair, before applying the color of choice. Bleaching pits can be tricky because although armpit hair tends to be coarse, the skin around the area is delicate. Beauty vlogger TheSassyElf highlights the importance of staying away from putting lightener on armpits in the case of particularly sensitive skin in her tutorial (video contains strong language). So wearing gloves to protect one's hands when dealing with bleach and developer is a must, and it's a good idea to wear clothes that you don't mind getting color stains on. Other tips include dyeing armpits when they are deodorant-free to avoid any freaky surprises.

Armpit hair -- bright pink or otherwise -- has been creeping into the spotlight over the past year or so, with celebrities like Madonna and Lily Allen championing the fuzzier look.