Testicles are the oval shaped organ responsible for the production of sperms and testosterone it also stores the sperm in people with penises. They are inside a sac of skin called the scrotum which hangs outside the body in front of the pelvic region.
Sources:
https://www.healthline.com/human-body-maps/testis
https://www.hopkinsmedicine.org/health/wellness-and-prevention/overview-of-the-male-anatomy
https://my.clevelandclinic.org/health/articles/9126-testicular-disorders