What are the “bases” of dating?

I’ve never really understood what the “bases” are. Example: If someone says they made it to second base, what exactally are they refering to?
First base?
Second base?
Third base?

I honestly don’t know, and would just like a little insight :)

The 4 F’s, french, feel, finger, f…

A Joke Every Day – 265 – 5th Base