Sorry, just saw this! This middle-age straight man (idc if he's initially straight or gay) becomes intrigued with this really quiet college student (Youichi). The middle-aged man (Sakurai) starts falling in love with Youichi and Youichi starts opening up. He was someone who never showed expressions and such, but he starts opening up and realizes he fell in love with Sakurai. I think its their characters that really make it for me.
the no expression part is kind of like http://www.mangago.me/read-manga/bukiyou_na_silent/.
the plot is kind of like http://www.mangago.me/read-manga/tatoe_toraware_no_koi_demo/ or http://www.mangago.me/read-manga/ten_count/ or http://www.mangago.me/read-manga/count/
I'm looking for yaoi/shounen ai manga that are similar to this one http://www.mangago.me/read-manga/hana_wa_saku_ka/.