A fork of Rural Dictionary
When you're outside having sex and you're ass is facing the wind and the wind blows up your arse a bit. Like if you part your arse a bit it'll get wind up it.
Y'know when you're at the park and you get wind up your bum crack just at the wrong time and your whole body shrivels up into a little raisin and you pull this face...
Facex is like sext (a mix of text and sex, meaning text sex) but instead uses the medium of Facebook for conversation.
Adam: Hey Sarah, wanna Facex?
Sarah: What's that?
Adam: It's like sexting, but on Facebook.
Sarah: Go on then.