So your best friend was supposed to hang out with you, but she blew you off again, probably to hang out with the latest guy she's fucking. She can see that you feel sad about it so she feels bad and decides to be nice...and offers to let you jerk off to her. Eventually she gets so horny watching you that she has to cum at the end, asking to cum together and for you to cum on her! She teases you throughout about how you're so in love with her, so head over heels, so enamored with her