The main purpose of good sex for a lot of people is to derive pleasure.
While you can do so by having sex with another human, there are other ways of achieving this and one is through the usage of sex toys.
Sex toys are devices and objects used primarily for the purpose of achieving sexual pleasure.
They can either be battery-powered such as dildos and vibrators or they can be other forms of objects that enhance sexual satisfaction such as swings, bondage, cuffs, slings, sex ramps, etc. You may read more about them here.