six up, four down.
Boys don’t float.
“blue bttm” begins with the sort of merboy logic that makes perfect sense as long as nobody stops to ask how breathing works. There is desire, a little bravado, and the old temptation to make everything happening underwater sound like a joke.
But the language keeps letting other signals through: missed calls, warnings, Mayday, and numbers that seem to mean more than they explain. “Six up / four down” can sound like a chant, a coded message, or a count that the listener does not have enough information to finish. The song never supplies a tidy decoding key.
Sinking can be an invitation, a performance, a consequence, or simply what happens when somebody decides not to swim. Even rescue is complicated here: the person who knows how to pull you toward the surface may also be the person who persuaded you to go under.
It is a funny song until you notice how frequently somebody seems to be trying to get a message through. Then it can still be funny. That may be the less comfortable part.
Is “blue bttm” supposed to be a warning or a flirtation?
Both can use remarkably similar language. I like that the voice can sound completely delighted with itself while something else is trying to come through underneath.
What is happening in “six up / four down”?
It can be a code, a count, a little chant, or a clue that somebody already understands. I don’t think the listener needs to solve it to notice that the numbers have changed the mood.