Jack Off, Jill Off - Slang for male and female masturbation

Jack Off - term used for male masturbation (manipulation of the penis to orgasm).  Male masturbation helps to eject old sperm from the genital tract.

Jill Off - term used for female masturbation (stimulating the genitals until orgasm is achieved), sometimes also referred to as Jilling.  Female masturbation helps clean the area around the  cervix.

Masturbation can be solo with a partner, using hands only or incorporate a sex toy.