Hydraulically-driven vibrating massagers. Devices for 
massage and / or 
sexual stimulation are vibrated and / or rhythmically deformed. The devices have at least two, and normally three elements as follows: (1) One or more hydraulically driven sacs or tubes within a 
massage and / or 
sexual stimulation device which are constructed with walls of intentionally varying modulus; (2) A hydraulic 
actuator to move 
hydraulic fluid into and out of the device (1) (3) Optionally, a flexible hose or hoses connected at one end to the 
sexual stimulation device or devices and at the other end to the hydraulic 
actuator. The particular devices actuated by the present invention can include various prior art 
massage and / or sexual stimulation devices, including 
muscle massagers, dildos, and 
penis rings (with or without attachment to secondary anal stimulators), sexually stimulating underwear, and two-ended dildos intended to anchor on one end in a 
vagina and / or 
anus, for example. For purposes of this disclosure, “sexually stimulating devices” and other similar language should also be understood to include massage devices that are not specifically intended for sexual stimulation. Compared to prior art vibrating sexual stimulators, the devices of this invention are capable of more complex 
modes of motion and both higher amplitude and slower deformation rates. The hydraulically actuated sexual stimulators of this invention are powerful, compact, quiet, and have low rates of 
heat generation compared to prior art electrically-driven vibrating sexual stimulation devices. In addition, the devices can be conveniently heated or cooled via the 
hydraulic fluid.