MC and Mashiro going on a road trip!!! Hopefully they can fix their minor issues and strength their relationship for the better.
Ui putting the moves on her 'best friend'/'Roommate (Well not really roommate but Ui comes over to stay a lot that sleeping in the same bed is that big of a deal)'
Ui probably thought there is no chance that Nagisa will accept her feelings (Probably would have gently reject her) so may as get a single kiss as a consolation prize.
Ui uses sneak kiss
Nagisa is confused
Nagisa listening to radio while driving and hears the song 'I kiss a girl and I like it~!'.
Nagisa slamming her head into the driving wheel horn as she groans trying to sort out her current feelings.