In Korea, "couplehood" is a Konglish (Korean English) term meaning 'a couple dressed the same.' I'm not sure how widespread it actually is, but I do know that in Seoul you'll see it fairly often if you walk around.
So, let's list the items, shall we?
1. Matching flip-flops.
2. Matching shorts.
3. Matching t-shirts with crowns.
4. Different color t-shirst: orange for female, green for male?
(Maybe there's a 'code of couplehood' I don't know about . . . lol).
5. And of course, the most important item of all: SITTING IN THE SAME POSITION!!! Heheheh . . .
I LOVE IT! (And no, I'll never do it).