In the beginning, a woman has a baby. This mother initially reveals her mental instability by repeatedly saying, to no one in particular, that "This kid is driving me CRAZY." Remember this foreshadowing.
At night, the mother likes to crawl over to her child, pick him up (but only when he is sleeping) and rock him and sing a song reminding him that "as long as I'm living my baby you'll be." This seems like a threat, particularly when the mother is berating her offspring for causing her mental illness during the day. She also threatens to sell him to a zoo (!) Luckily, her son grows up and moves out of this psychologically damaging environment and away from his mother who still has been compulsively rocking him even once he is a sleeping teenager.
But even after that... "sometimes, on dark nights," (shudder) "the mother would drive across town" and, "if all the lights at her son's house were out," she would creep through his bedroom window and covertly rock this unconscious adult man.
This is not cute, not sweet, not heartwarming. This is a mania, and her son needs to get a security system and possibly a restraining order. Imagine how this story would sound if it were a female asleep in her bed and someone was creeping into her bedroom at night out of "love" to watch her sleep? That would be horrifying, wouldn't it? (Or, you know, Twilight.)
Then, her manipulation grows worse-- she calls her son and warns, "You'd better come see me, because I'm very old and sick." Having grown accustomed to this type of emotional blackmail, he complies, and then is compelled to rock her and sing the song. When he returns home, he continues the cycle of emotional abuse by rocking and singing to his own daughter, poor thing. How he managed to ever produce a daughter with his mother creeping into his bedroom every night, I can't imagine.
In the words of Norman Bates, a boy's best friend is his mother.
Munsch, Robert. Love You Forever. New York: Firefly, 1986.
Love You Forever