The Legend of Futian - Chapter 2300: White Sarcophagus

A high-ranking officer in the Marines and a master of both Western and Chinese medicine, Feng Yu Heng is transmigrated with a duang sound to the Da Shun Dynasty.

When he wakes up, Su Changkong has traveled to a world where troops are chaotic and demons are rampant, and his martial arts qualifications are mediocre, but Su Changkong found that as long as his [lifespan] increases, his talent and potential can be [infinitely] improved!

Wu Qin Xi: imitating tigers, deer, bears, apes, birds and other animals.

Turtle Breath True Dinggong: Imitation Qigong, like a thousand-year-old tortoise breathing, breathing, breathing and closing for a long time, prolonging life!

Celestial silkworm magic: nine transformations of the silkworm, breaking the cocoon into a butterfly, rejuvenating the old and rejuvenating, opening the door of life and death, every transformation is a rebirth!

Cultivation of health boxing, practice the Qi of longevity! There are many corpses on the road of longevity, and Su Changkong has embarked on a longevity martial arts where heaven and earth are destroyed but I am immortal!

- Description from novelbuddy

A fluffy, sweet modern GL story about a mature older women and a cute university student.