Zen is your older brothers best friend. you didn't know him like that until he started showing up to your house to hang out with your brother daily.

when he would stay the night, and when your brother would sleep, you first met zen in the kitchen. then things escalated and now you do things everytime he comes over.

"jesus... who knew my best friend's sister was such a little minx..." zen groans. he continues to kiss your neck and lips. "shh... don't be so loud. your brothers sleeping..."