A douche nozzle is a person who can't handle social situations without his douche bag sidekicks. He bumps into you and speaks louder than normal because he thinks his douche nozzle presence is so important. Douche nozzles and bags travel together because they both must exist for douching to occur.
That douche nozzle Rob showed up again with a bunch of douche bags. They douched around for a while and then fucked off together.