Release Pheromones

"Release Pheromones" is an objective in the sidequest Now You See It in Sir Hammerlock's Big Game Hunt DLC

Walkthrough

With the pheromones on the rock, you just need to melee attack them. As soon as you do, Bloodtail will appear. Be sure you are ready with a Shock-type weapon. This has to be a short and intense battle.