Earning the right to ride in the front passenger seat of someone's car. This is also the direct opposite of "
riding bitch," where you are sitting center-backseat, sandwiched by your friends (aka: riding gay, riding whore). It is "shotgun"'s
responsibility for
controlling car temperature, changing radio stations, calling out landmarks, and flagging down hot girls.
Variations to "calling shotgun" can include paper/rock/scisors, coin flip, or being the first to yell "shotgun" when the driver pulls their car keys out of their pocket. Seniority rarely means anything when calling shotgun.