Wait so how do two girls..do it ?

with fingers (≧∀≦)
⁄(⁄ ⁄⁄ω⁄⁄ ⁄)⁄

They don't. It all happens in the mind..

Woodie is right. Lesbains don't exist it all happens in dreams and in the mind

Jokes aside, it depends on what preferences you have. Usually people use fingers. Some use tongue and some use a toy. The best example in that is the man's part in silicone. But one may find it to uncomfortable or hurtful to their privates or not like the feeling. That's why fingers is the most common option (●'◡'●)ﾉ

it's the same as doing it with a man minus the dingdong