Senbongi is Uehara's closest companion. Like Shiina, he also noticed the personality change that occurred between Uehara and Momoi. He develops an attraction to a changed Momoi (Uehara in her body) and often it comes to the situation when he tries to make out with her (and it is successful until Uehara quickly gets away). Other times it is trying to buying her affections, such like buying her a parfait when the two hang out so she would give him chocolates for Valentine's Day. Though some interaction between the two have proven that he does genuinely like 'Momoi'.
By the end of volume 2 and beginning of volume 3, Senbongi overhears a conversation between Uehara and Momoi and after realization of their personality changes finds out they switched bodies. Despite the fact that Momoi happens to be his best friend Uehara, Senbongi does not mind and continues to pursue him.