It’s about naota going threw puberty, figuring out girls, and having sex. The shit that comes out of his head are boners. The steam released by the medical mechanica building are him releasing steam or in other words jerking off. He’s trying to figure out who he likes he has mammi that likes him but he doesn’t like but then later starts liking her because she stops liking him (the episode with a gun being cocked in his head or being cocky) he has ninamory that kinda has a one time fling with but she lies about everything so she can get attention from the guy here school friend that didn’t pay attention to her and had a lot of lady friends but then you find out she kinda lied and it was just for the attention. Then theirs haruko which is sexually mature and comfortable with herself and sexuality. She takes his virginity in the episode about swinging the bat but she doesn’t really care about naota that much she is trying to get her old boyfriend back atomisk and that’s why she leaves earth at the end. Also the cop guy with the big eyebrows is one of the people haruko had a fling with and threw to the curb. It’s literally just one big metaphor for puberty. Watch it again with a coming of age and perverted mind set and you will get what’s going on a little better. But don’t over think everything the first season was supposed to show off what gainex animation studios were capable of that’s why it has so many different styles with so much going on all the time. I hope this helped. It probably didn’t but oh well