" I took a picture of you drooling at your desk, Youko ! "---Arima
After high school ended, he attended a university in the Kansai region. He and Youko stayed in touch for half a year, but slowly grew apart. Because of not staying with Youko Tsubaki, that implies that Youko was never able to Drool Bond with him, possibility because, like Ueno and Ogata, he does not have drool capabilities.