One way Manabe uses to get Haruka's attention is to deliberately think of her in erotic situations.
The way the ESP "recruits" Haruka in episode 2.
Manabe asks if anyone in the ESP club room has seen Haruka, he's told to ask the girl in the box.
This exchange in the third episode as the ESP club is splitting up to go home.
Mifune: Okay, Manabe, make sure you see Kotoura home. Manabe: *salutes* Roger! Daichi: ...and no making a move on her once you get her home. * beat* Kotoura: Hey! Aren't you going to respond?!
In the third episode, when Manabe finds out that Haruka plans to cook for him, we get a far shot of him rocketing up literally several stories in the air with a loud whoop and odd sound effects. A few minutes later when they part ways, Manabe is still thinking about Haruka. The shot lingers on Haruka until suddenly the sound of Manabe whooping and rocketing into the air again is heard off screen and Haruka flinches.
When Manabe gets in an argument with Kotoura's grandfather over their perverted fantasies of Kotoura, it shows that they are Not So Different.
The entire sequence where Manabe and the ESP Club "capture" Kotoura in Episode 4.
In episode 5, whenever Haruka gets happy, she rolls around on the floor like a madman and crashes into a pile of cardboard boxes which fall down on her.
Also, the whole MORI! thing. The promotional ad Moritani's family did to promote the dojo has them making a weird pose with Hiyori in the center. Imagining Hiyori saying MORI! in that ad makes Haruka spit-laugh for the rest of the series. Manabe does it on purpose in episode 5 just to mess with Haruka when consoling a crying Hiyori.
Played Up to Eleven the first time this happens, within the first few minutes of the episode. It flashes "Kotoura-san: The End" over the screen when the boxes fall on her, implyingshe was crushed.