Sleeping in the same bed as your fuck friend for three or more nights in a row. Once this has happened, it is an indisputable truth that they will end up dating (or getting back together again).
Where ya goin?
I'm have to uh, study.
No you don't.
I- I don't know what you're talking about.
This will be night number 3, right? Once you are consecutiving you can never turn back.