In 2015, Madonna finally explained what happened that fateful night. Basically, she was having some guy trouble. Her then-current boyfriend, as she explained to Howard Stern, had got her "all riled up on life in general," so when she went on the show, she was feeling "very gangster." Which is fair considering that at the time, she was dating none other than Tupac.
Yes, THAT Tupac.
It isn't known when Madonna and Tupac started dating since they kept their relationship a secret, but what IS known is that this wasn't just a fling. The pair had major feelings for each other; a fact we only know because in 2017, a three-page letter from Tupac to Madonna went up for auction.
The letter, which was written in 1995 while Tupac was doing time, talks a lot about the pair's relationship and his own insecurities -- including the fact that throughout their relationship, he ("a young man with limited experience") was intimidated by Madonna's sexually-aggressive public persona. The letter also sheds some light on why the two broke up. Basically, it came down to the fact that although going public with their relationship would've helped her career, it would've not only hurt his, but (in his mind's eye) "be letting down half of the people who made [him]."
Luckily, Madonna still seems to celebrate the late rapper's birthday on Twitter, complete with TWO cake emojis. It's a sentiment too beautiful for words.