jump hump

From jump +‎ hump, as a form of reduplication.

jump hump (third-person singular simple present jump humps, present participle jump humping, simple past and past participle jump humped)

1. (slang, chiefly Mormonism) To soak (have penetrative sex without hip thrusting), typically on a bed, while another person repeatedly jumps close by so as to cause the penis to move back and forth inside the vagina.

• The term is chiefly used in reference to Mormons engaging in premarital sex, who purportedly believe that hip thrusting is a necessary aspect of sex which can take one's virginity.