I call shotgun
In life in North America ,
riding in the front passenger seat is seen as very desirable. There is often a lot of competition for
this. Often you will see characters say
the phrase, "I call shotgun," or "shotgun". This means that they are declaring that they
will sit in the front passenger seat.
This expression originated when people driving wagons needed
someone to sit next to them with a shotgun for protection. These days, no gun is required.
Check out this video. I don't agree exactly with all the rules, but they make some good points.