The Writing's on the Wall Lyrics
You know it’s not different for me
We’re less than a zero sum game now
And baby, we both know that’s now how it’s supposed to be
It seems like forever since we had a good day
The writing’s on the wall
But I just wanna get you high tonight
I just wanna see some pleasure in your eyes
Some pleasure in your eyes
And we both fall apart
Then you bring your mind to rest against mine
But the mind has no say in the affairs of the heart
It seems like forever since we had a good day
The writing’s on the wall
But I just wanna get you high tonight
I just wanna see some pleasure in your eyes
Some pleasure in your eyes
But the mind has no say in the affairs of the heart
It seems like forever since we had a good day
The writing’s on the wall
But I just wanna get you high tonight
I just wanna see some pleasure in your eyes
Some pleasure in your eyes
Just wanna get you high
Just wanna get you high
Even if it’s the last thing that we do together
Even if it’s the last thing that we do together

I love the mix of inevitability and hope in this song. They know this relationship is ending but still have love and fondness for each other. Best to go out on a good note if you have to.
BTW, if you haven't seen this video, it is NEXT LEVEL, full of trompe-l'œil and other amazing visual trickery, all in one take.

He knows the relationship is almost over and that they need to break up, but he doesn't want to think about it tonight. I'm not sure if "getting high" is literal or metaphorical, but either way "getting high" means forgetting all that bad stuff for tonight, focusing on what's still good and enjoying each other.

I think it's clearly about "The writing on the wall", a metaphor often used to describe an omen or premonition of doom. There are all these illusions that people build around a decaying relationship to keep it alive, which they brilliantly expland on by using the music video for this song. Lots of things just don't appear to be what they once were; Emotion seems to be lacking in most aspects of this relationship, making them " less than a zero-sum game now". Furthermore, they "both know that's not how it's supposed to be". "It seems like forever / since we had a good day", he says.
At that point, in that kind of ending relationship, sometimes you really just want to get high with that person and "just want to see some pleasure in [their] eyes." Sex (and yes, sex while high) between long-time lovers is filled with emotion. In the video, the words "I understand you" morph into "but I don't". This is a desperate plea that we have all thought about when a relationship is over, but emotionally, it doesn't feel that way yet. Since "the mind has no say on affairs of the heart", the sex they have is a replacement for the love which has clearly withered.
Clearly a super dancey tune, with a ridiculously sad song.

How I see it - because it fits exactly what I've been going through. Two people who had some sort of feelings for each other (could be romantic, or in my case, platonic "besties" but underneath there is an interest by one side). He's coming the point of realizing that they are officially falling apart. But she means so much to him. It had been an amazing friendship. He remembers the good times - painfully. He knows she is going but wants to just hang out and talk one last time. He knows she feels bad about him deep down but he doesn't want her to feel bad. He just wants her to be happy...even if it means pain for him.