Uchi No Otouto Maji De Dekain. Upd -
: In Japan, the relationship between siblings is often depicted in media as very close and affectionate. The portrayal of a cute younger brother or sister is a common trope, capturing the hearts of audiences.
The phrase you're referring to seems to be associated with a manga and anime series titled "Uchi no Otouto no Mamahaha, Boku no Ototo, Mahou Kaite Zealous." However, there's a more commonly known work that might relate to what you're talking about: "Uchi no Ototo" or more accurately, "The Ancient Magus' Bride" or other works with similar themes. uchi no otouto maji de dekain.
It’s simple, expressive, and adaptable. You can use it in real life when your younger brother lifts a sofa by himself. You can use it in a tweet about your favorite anime character. You can even say it ironically when your “little” brother eats an entire pizza in one sitting. : In Japan, the relationship between siblings is