An adult toy includes an elongated elastic body which has an inner space defined therein and an opening defined at one end thereof. A sealing device or a one-way device is disposed at the opening to seal the inner space. The user can make fluid flow through the sealing device or the one-way device into the inner space to inflate the elastic body, or release the fluid out of the inner space to deflate the elastic body. When the fluid is completely released, the adult toy is greatly reduced in size and is easy to store or carry. The elastic body may connect with a reservoir. The fluid received in reservoir can be forced to enter the elastic body and the fluid received in the elastic body can be released to the reservoir, thereby adjusting the stiffness and the size of the elastic body.
