What does 90/10 mean?

Usually means 90% for one thing and 10% of another thing. He mixed his drink 90/10 water to alcohol.

According to the urban dictionary:

A 90 percent hand job, 10 percent ********.

no such thing. you cant have 90 out of 10

lol, look it up on urban dictionary! :)

You have x-ray vision in one eye, and the other is blind.