This can be either a button that you press

The vibration is controlled by a switch on the bottom of the toy's base. This can be either a button that you press or a dial that you turn to increase or decrease intensity. The base is where all of the wires connecting your app vibrator to its power source will be located, so it's important not to cover up this part with anything that would block access to those wires.The switch itself may be located in different places depending on what kind of toy you have: it's usually at the base of toys with shafts and underbellies (like rabbit vibrators), but some insertable vibrators have switches on their tops instead. Either way, don't forget about them!