Everything was going normal until one day. That day, I returned home from a week trip with my friends. Derek was fixing the pipe in the kitchen while grandmother, mom and my younger sister were watching him. Since Derek was wearing a white tight tank top and a mesh short, his muscles were outlined very well. From everything my sister told me, I guess Derek finally became one with our family, not as a son but as a man of the house.
My grandmother and my mother seemed weird lately. But my mom was the weirdest one. She started wearing clothes that are tight or skimpy, and tend to get shy around Derek. And Derek looked very intimate with mom. I couldn't help but feel suspicious about them. And that's when I decided to spy on them.
Derek would touch my mom's butt anytime he had a chance. I don't know if he did it on purpose or not, but mom didn't stop him. I found out that mom started wearing nightgown lately, and Derek didn't wear much at night, just wearing his plain blue boxers or his black boxer briefs. Everytime I accidentally catched them wearing like that, I started to breathe heavily as wild imagination appeared in my head.
Yesterday, mom suddenly said that she was going to the cinema with Derek. Derek asked her to go with him to see the latest part of a movie... I don't know... And when they came home, both of them seemed drunk. They were standing very close to each other, almost like a couple, with hands on each other's body. Derek seemed very excited while mom looked shy and nervous.
I was worried but couldn't ask them anything. Then suddenly, Derek said that they should take a shower since they were both sweaty from the hot weather. I felt something odd at the way he said it to me so I decided I need to do something. I told them to take a shower before go to sleep and then I pretended like I went back to my room to sleep. I hid at a corner to spy on them and what I saw was very shocking. My mom and Derek hurriedly grabbed each other and kissed passionately. While they were kissing, they also took off their clothes and went inside my mom's bedroom. I quietly came near the door and all I heard was sloppy sounds, moans and Derek's pleasure noises. Everything followed that were the sounds of them having sex wildly and passionately. And I couldn't do anything.
...
Then I opened my eyes. I wonder if everything was just a dream. Looking at my phone, it was 5am. I quickly got out of my bed and went out to check on Derek and mom. Thank god, Derek was still sleeping in his room and mom was preparing breakfast in the kitchen. I let out a sigh, feeling stupid for being afraid of something only happening in my dream.
When I was ready to go back to my room, I noticed my mom's room was opened. I felt like something was calling me in my mother's room, so I decided to check out what it is. When I entered her room, I was frozen as I saw that 'thing' on the floor next to her bed. It was Derek's briefs - which I accidentally saw him wear yesterday...
I really don't know what to do now, but I do turn-on in this situation. Fuck!