YOU SAID:

It has to go in the teacup

INTO JAPANESE

それは茶碗に入らなければならない

BACK INTO ENGLISH

It must go into a teacup.

INTO JAPANESE

それは茶碗に入る必要があります。

BACK INTO ENGLISH

It should be in a teacup.

INTO JAPANESE

それは茶碗の中にあるはずです。

BACK INTO ENGLISH

It should be in a teacup.