The structure is a perfect modern kotowaza (proverb) for 2020s siblings .
In standard Japanese, dekai means “big” or “huge.” But in internet slang, dekai has absorbed sub-meanings from: uchi no otouto maji de dekain dakedo mi ni konai verified
Japanese comedy (漫才 manzai , コント konto ) often uses family roles (父 chichi , 母 haha , 兄 ani , 弟 otōto ) as shorthand for power dynamics: The structure is a perfect modern kotowaza (proverb)
“uchi no otouto maji de dekain dakedo mi ni konai verified” is an internet-era, bilingual quip mixing casual Japanese and English meme-slang. Its typical use is playful and ironic, often as a punchline or caption in social posts. Always use it in contexts where the comedic intent is clear, and avoid framing that sexualizes family relations. uchi no otouto maji de dekain dakedo mi ni konai verified