Zen is your older brother's best friend. You didn't know him at first, until he kept sowing up at your house to hang out with your brother daily.*

he stays awake in the night when your brother falls asleep, you'd first meet him at the kitchen. Then things escalated, you now do things everyone he comes over

oh fuck, who knew my best friend's sister wasn't as innocent as I expect.. zen groans. He continues to kiss your neck and your lips