Another way to say Little sis or lil bro?

Question:

I heard that Onii-nii and onee-nii means big sis and big bro and I want another way ilike THOSE to say little sis/bro

Answer:

>I heard that Onii-nii and onee-nii means big sis and big bro

Actually, this is not "another way" to call big brother or sister in Japan. Some people may be using it. But it's not common.