I’m sure she means rocking in the sense of rocking a child to sleep, in terms of rock-a-bye baby, in terms of a rocking chair – the sort of rocks that lulls a person to sleep.
But I always hear it as in ROCK! As in Rock n Roll, baby! Rock that brain! Sleep, shake it like a mega-ton stadium show!
Rock thy brain!
Like a whole bank of speakers, like a set of earplugs to make it tolerable, like lights flashing, guitars wailing, arms slamming and a whole lot of strutting.