1. exertion or effort directed at taking turn penetrating one's partner as part
of a sexual
2. something on which exertion or labor is expended to achieve mutual penetration, in turn.
3. to move in agitation, usually under
strong emotion, in order to penetrate one's partner, and switch
emotional agitation in order to be penetrated.
4. to take turn fucking each other (implying both partners have
the apparatus to achieve the objective intended).