I like to think of the song as Ride saying "I am all of these things, so they cancel out and so I am nothing" hence, "I'm a bullshitter, I'm a etc" the idea being "I'm on the moon because you can't tell what I actually am because I'm all of these things". With that in mind, feng shui is harmony with one's consciousness, the idea of catering to one aspect of self; this line, to me, is saying actually fuck that sense of self by asking what's in that spliff, which is both weed and tobacco, two senses of self, hence, "impurified conduct". This is why we're on the moon with this album, because they are all of these things and so they are nothing, hence the repeated "I'm not shit" throughout TPTB. It gets even crazier because this isn't the only interpretation when it comes to their lyrics; while I view it this way, there also exists another way to perceive it. They aren't anything because I perceive it this way and someone else who listens to it can also have a valid interpretation, so those two cancel each other out and it strengthens the idea that they're on the moon because the interpretations contradict each other. This also goes hand in hand with something Andy said in an interview I think, where he explains something to the effect of "people dig around in our music for the trash, and it the way they look at it acts as a feedback loop". They design their music so you see yourself in it essentially, that's why they take their ego out. All in all, meta as fuck, which is why I really appreciate the concept especially of TPTB.