Note: All of these projects assume you know a little bit about electronics, and know how to solder. The radio control toys are much easier to build than the pager control variety. For the radio toys, a simple knowledge of soldering and the ability to identify simple parts is all you'll need. Don't attempt to modify a pocket pager unless you're confident about working in very tight spaces and think you can solder on a tiny circuit board without damaging it. Electronic components are damaged by heat; use only enough heat to make the connection. With the pager controlled toys, it's helpful to use a soldering technique called "reflow soldering," where you coat the part you will be soldering with a layer of solder, melt a small amount of solder onto the board where you'll be connecting the part, and finally bring the two parts together and heat the connection with a soldering iron. Here are pictures of some parts you'll need:
Solid-state relay. The two leads marked "~" are connected to the sex toy. The leads marked "+" and "-" connect to whatever you're going to use to switch the toy on and off. These are available through most electronics supply stores.
Diode. The end marked with the stripe is the cathode.