Digital Salute

noun - a salute is a sign of respect. It is also a traditional way of showing your hand to make it obvious that you do not have a weapon in it so are not threatening.
A digital salute is a friendlier version of that - needing only a single finger. The middle one. Usually served with beer & friends.

hot-gf: “Selfie?”
R2: “well let’s all show the digital salute for that - smile!”