When you are talking to someone online, and you both ask a question at the same time, and you both answer each other's question, and you get into two conversations at the same time.
This is normal when text messaging, but annoying when facechatting, hence the name facetexting.
Brad: You going to Tiffany's party?
JayJay: Did you see the Lakers game?
Brad: Yeah that touchdown at the end was amazing
JayJay: Yeah, but I don't think it's gunna be very good. Oh yeah, I punched the air when Tommy Nelson scored.
Brad: It will be good! I'm going. I know right, I punched the air really hard.
JayJay: Stop Facetexting dude!
Talking to someone on facebook while across the room from each other. Then looking up at the person to see if they got the message and laughing. Dirty messages are to ensue.
Sexting over Facetime on any Apple device. Could resemble, but not does necessarily bear any resemblance to: skexting, fexting, sexting, texting, and skyping. Pictures may or may not be involved.