Jumyou wo Yuzuru Tomodachi no Hanashi.

Miyuki and Hikari are childhood friends and longtime gals who are now in their third year of high school. They spend their days doing silly things and having fun, but Hikari has a special ability: she can see other people's lifespans and give them her lifespan. Miyuki wants Hikari not to use her ability, but Hikari's lifespan is getting shorter and shorter...

(source: Comic Walker, translated)