I first heard "Sealion" in the Travolta movie 'General's Daughter' and it stuck in my head to the point of 1. Buying the soundtrack and 2. Researching the song further.
What I found were many variations such as above in this thread. But my conclusion was this: 'Sealion' is apparently slang or coloquial for 'She's Lying' and is a "she said-she said" conversation (to a musical tune) between two young girls or two rivalrous women.
In my readings, 'She's Lying' comes from a ery old work song sung by southern field hands to pass the toiling hours – similar to the chain gang practices such as depicted more recently in the Clooney Movie 'Oh Brother, Where Art Thou' and others.
The two girls or women mentioned could have been house servants at a time when coffee and tea were well off limits to all servants. And when you think of the lyrics as a juvenile tattle tail incident, it becomes clearer.
"She drank (some of your) coffee" ==>   <== "(No I didn't) She's lying"
"She drank (some of your) tea"    ==>   <== ""(No I didn't) She's lying"
Like many, the lyrics, such as Nina Simone's variation referring to prostitution, have branched.
And I'm sure there are more. Never the less, this music is more than just a song. I feel it to be a piece of African-American culture that has become a precious and significant piece of the whole American experience. Thanks go out to the Library of Congress for recognizing and treasuring several original recordings for all of us to appreciate on several levels.