Koi wo Shiyou is a song created for Rohto Pharmecutical's advertising campaign Koi Tsuru Hada Kyun, a short narrative told in commercials concerning a high school romance. Although the story by itself is not connected to the Confession Executive Committee ~Love Series~ , LIPXLIP does end up singing its song and making a cameo in the third installment of the campaign.
This song is featured as the 34th individual song on the Niconico playlist for the franchise.
The subjects of the campaign, a fat girl and an athlete who acknowledged their love for each other in the second installment, prepare for an amusement park date. The girl spends her time trying to figure out what to wear and making a picnic lunch for the two of them, while the boy tries to practice making a cool impression on her. In both scenarios, they imagine their idea of the perfect day out, culminating in a kiss on the ferris wheel. When reality settles back for them, they go back to preparing and end the video washing their faces, the thought of their fun day ahead of them still in their heads.