Calls have not been going Atletico Madrid's way in the Madrid Derby. They should have had a pair of penalties, but have been denied on both occasions, and they've picked up a few soft reds. Diego Simeone probably wanted to get in the referee's face himself, but might have been concerned with the message that would send and would like to stick around to make tactical adjustments, so he improvised.
He sicked assistant German Burgos on the referee. The results were glorious.
Burgos, if you didn't know, is a former Atletico Madrid goalkeeper and has been Simeone's assistant for three years, in three different countries. He doesn't exactly have a reputation for this sort of thing and isn't a random rogue assistant -- he's Simeone's right-hand man. It would be surprising if this was an emotional reaction, not a planned tactic.
Also, applause to Simeone for the spectacular dismissive wanking motion.