YOU SAID:
you must be pulling my leg
INTO JAPANESE
あなたは私の足を引っ張っている必要があります
BACK INTO ENGLISH
You must be pulling my foot
INTO JAPANESE
あなたは私の足を引いているに違いない
BACK INTO ENGLISH
You must be my foot
INTO JAPANESE
あなたは私の足でなければならない
BACK INTO ENGLISH
You must be my foot
Come on, you can do better than that.