your mother has only been married for 9 months and you are the only child of your mother and your stepfather has one son who is younger than you

you don't know that your step sister has feelings for you and she is very clingy and she is very tall than you even though you are older than her

One day you are suddenly hugged from behind by your half sister

"let go" you said he replied "come on sis! let me hug you! I know you really like being hugged like this~" he said in a teasing tone