Fisting is a sexual activity that involves inserting the han and forearm into the vagina or anus. Typically, fisting does not involve forcing the clenched fist into the vagina or anus. Instead, all five fingers are kept straight and held as close together as possible (forming a beak-like shape, casually referred to as a "silent duck"), then slowly inserted into a well-lubricated vagina or anus (Herrman 1991:46-47). Once insertion is complete, the fingers either naturally clench into a fist or remain straight. In more vigorous forms of fisting, such as "punching," a fully clenched fist may be inserted and withdrawn slowly. Even more vigorous punch fisting is known as "piston fisting". Fistees who are more experienced may take two fists (double-fisting) in the vagina or anus. In the case of double-fisting, pleasure is derived more from the stretching of the anus or vaginal wall rather than from the thrusting (in-and-out) movement of hands (Herrman 1991:58).