A sexual stimulation device includes an elongated dildo housing sized to be received within an orifice of a human body, the housing defining an internal cavity extending along a longitudinal axis of the housing, a mass laterally constrained within the cavity and movable linearly along the cavity, and an electrically driven actuator disposed within the housing and operably coupled to the mass. The actuator is operable to accelerate the mass along the cavity and to thereby induce a longitudinal reactive acceleration of the housing.