One of the double-take moments that makes this song so brilliant: One would expect that a drinking, clearly stressed-out man might have a morning appointment with a doctor or headshrinker, or perhaps plans to see a lover or close friend.
All Golden Boy has waiting for him tomorrow is dehydration and a headache.

Cassandra was a Trojan (Greek) woman of legend; supposedly, the sun god Apollo blessed her with the gift of prophecy, but she was later cursed so that no one would believe the prophecies of tragedy that she gave. She was first labeled a naysayer and exiled, then forced to watch helplessly as the horrible events she foretold came to pass.

A true prophet may not see every little thing coming, but you can bet they’ll still be saying “I told you so” at the end of the day.

Clever reference to the 2012 anthem Niggas in Paris

He can’t make it rain on her now, but offers a metaphorical voucher to the dancer to do so at a later date (making it rain=throwing money on a ho, and “rain check” is a figure of speech that originated from baseball-when outdoor games are called on account of rain, people with tickets are given rain checks to see the game when it occurs on a later date)

Jake Gyllenhall played a gay cowboy in the 2005 film Brokeback Mountain.
Also, “Broke in the back” sounds like it could refer to having your asshole torn open after anal sex.

The fact that Jonwayne’s carrying “the virus” may be a play on being “sick” (as in dope).
What else he’s carrying, however, is a bit of a mystery.

Enzymes are chemicals produced in living organisms that facilitate some of the chemical reactions that are necessary to sustain life.
Mice and rats are often used in laboratories as test subjects.