Start a private match on Siena (need at least 4 people to do this depending on mode). Find a spot in a crowd of people (near the vendors) and hang out for 3 minutes. I put on the blender perk, though I don't think you need it since we had a few low levels in our party when we did this.
Once you are done your 3 minutes you can exit out of the match.
As commented by neeker75, this 3 minutes is cumulative.