It's absurdism, based on a gag manga. Every episode goes as follows:
(a) Ishida and Asakura have a thirty-second conversation in the classroom. No one else. Just them. It always starts with "Ishida, I have a request" and "Very well, Asakura, I shall listen to your request."
(b) a thirty-second title sequence. It might appear that the show's full of women with huge boobs, but in fact the two biggest offenders are cross-dressing men.
(c) sixty seconds of oddness. Don't expect reality. Ishida murders another boy called Yamada in most of the episodes, but it's never permanent. In ep.7, Yamada builds a cartoonish robot and no one can tell the difference between him and his creation. In ep.11, Ishida gets Yamada's head all the way up his arse. Ishida can also throw Asakura so violently into the air that he reaches outer space and crashes into the flying saucer of aliens intent on a boob invasion of Earth.
Our heroes are stoic and under-emoting. Asakura loves boobs so much that in ep.6, he's offensively unresponsive when in bed with his teacher's daughter. (Teacher gave her to him and she's dressing up in various outfits to try to bludgeon him out of his coma, but nothing works. "Where are your boobs?")
He also pauses at the end of all his senten... ces.
Ishida is more distinctive. Imagine a stone-faced gay stalker who's also Kenshiro from Hokuto no Ken. Ishida wants to open a flower shop with Asakura and keeps murdering Yamada in rage at Yamada's rival plan to open a bookshop with him instead. He also never smiles. His friends try to coax facial expressions from him in ep.11 and the results are terrifying.
I should explain one cultural reference in ep.3. Anime occasionally uses elephants to represent penises. This is normal in Japan and suggests nothing about size, but merely describes the shape. (Two ears and a trunk.)
Is this show funny? Sort of, maybe. It's odd. I didn't mind watching it.