Obasan is a direct Japanese pronunciation, the original meaning is: sister-in-law, aunt. Generally refers to middle-aged and elderly women. To Hong Kong and Taiwan, to the word has actually been tarnished, derived from: three eight type of old women.
Small sister is a term that came from Taiwan, from Taiwan, the evolution of small tai bao, small sister originally refers to striptease and other nasty dance TABLEDANCE, and later referred to those girls hooligans or hooligans mixed with the girls
Shota comes from the Japanese manga "Iron Man 28" hero Kaneda Shotaro! Nowadays, it is mostly generalized to refer to very attractive little boys.
Corresponding to Shota, LOLI (Loli) refers to a cute little girl.
Add to that
Shota = cute little brother