He want that...
Similar to Big Sean’s chorus in his song “Dance (A$$)” with the repetitive word throughout the chorus.
Cake is usually referenced to a girl’s ass but can be referenced to her pussy, too, in this case. But she knows her ass is phat and knows he wants to be all up in it.
To help improve the meaning of these lyrics, visit "Birthday Cake" by Rihanna Lyrics and leave a comment on the lyrics box