It's bad to become aroused in a public setting.
Bobby is riding the bus back home and is stuck in rush hour traffic.
Bobby wants to entertain himself.
Bobby listens to some of his favorite podcasts to pass the time.
Bobby watches porn on his phone while on the bus and gets a boner.
Bobby gets to learn about interesting topics and time flies as he reaches his bus stop.
The other riders feel uncomfortable because of Bobby and think he is a pervert and Bobby gets embarrassed.