A Thousand-Year-Old Snake Demon Has Possessed Me! Double Cultivate or Die

[A thousand souls share one body and accompany beauties; dual cultivation proves the Dao and takes you to the heavens!] A kindhearted mortal boy rescues a snake, only to discover it is a thousand-year-old snake demon. After an ancient lascivious beast forcibly implants a demon core in him, he unexpectedly embarks on the path to immortality. The catch is that he must dual-cultivate with a female cultivator every month, or he’ll drop dead. Wait, who says that’s a catch?