You shouldn't ask someone else's boyfriend to prom.
Kelsi was hanging out with her friend, her friend's boyfriend and several other kids in her class talking about the prom.
Kelsi wants to ask one of the guys to prom.
Kelsi asks one of the other guys in the group to go to the prom with her.
Kelsi asks her friend's boyfriend if he wants to go to the prom with her.
Kelsi's friend is excited that they will both have a date to the prom.
Kelsi's friend gets mad at her and gives her the silent treatment for a week.