Name: Kanojo no Kagi o Akeru Houhou
Associated Names: 彼女の鍵を開ける方法; 裤妹我爱你; 褲妹我愛妳; Kanojo no Kagi wo Akeru Houhou; The Way to Open Her Lock
Mangaka: Nakata Yumi
Taken from Mangaupdates:
Haruma's first impression of the new transfer student, Chitose, would be striped panties. Running into her in the hallway, Chitose's panties greet Haruma before they even know each other. Immediately, Haruma finds himself attracted to this mysterious panty girl, only to find out that she is transfering into his class AND she's going to be the new house keeper at his apartment.
(Not to mention her little problem with a rather strong exhibitionism streak...)
Let the skirt flying romance comedy begin!