When one or one's gf/bf starts talking about other guys/girls excessively/obsessively. Also when they get very interested in other people.
Rox (Mer's gf): *talks about "cute kid in math"*
Mer (Rox's bf): you should take pictures of him and show me exactly how "cute" he is.
Rox: atleast I'd have pics of him
Mer: wait what? you never said anything like that about having pics of me.
Rox: sorry I got sidetracked!
Mer: SIDETRACKED! SIDETRACKED?!
To get distracted for a while halfway while you're doing something.
"Have you finished that research yet?"
"SHIT! I got sidetracked! Been playing Club Penguin all this while."
Social context: Meet (as in see again/ or for the first time) a person who you don't really appreciate being with, and getting stuck with him/ her.
Jonathan, Mark and Darriel are waking towards the balcony in a party. On the way, Darriel is spotted by her high-school colleague, who is a nerd (while Darriel is really cool) and she HAS to talk to her for a while.
Once in the balcony, Mark says:
- Hey, where is Darriel??
Jonathan: She got sidetracked!