When someone is on the phone, texting or are otherwise occupied whilst their friends are in the same room having a conversation. Much like the common internet meme with the picture of the nerd reading a book while a girl is pressing her tits up against him, there is a caption that reads "GTFO BITCH, IM DOING SCIENCE". In this instance the nerd is doing science
Steve: Hey did you see that band play last night?
Bruce: No, how wehere they?
Steve: they were fucking awesome!
Rob: *off in the corner texting his girlfriend
Bruce: Wow, Rob needs to stop doing science and actually enjoy his friends!