One of the least desirable of the Wings that anyone can get, they're earnt when someone pukes into your mouth when you're kissing them, or you puke into someone's mouth during a kiss. Named due to the colour of the vomit.
"Oh man bad news, Sarah puked in my mouth last night during our first kiss."
"Dude that's rank, but you are the first person I know to get their rainbow wings, haha" OR
"I got my rainbow wings last night mate, puked into Jenny's mouth at that party"
"John, you're wrong."