The siblings
Friends, I believe siblings are set up in a situation where they have sexual urges they crave to fulfill in the moment.
Aside from my sister, I don't have much interaction with girls. It was my 25th birthday and we decided to go out on a helicopter ride for fun. My sister of 23, is a very modest person due to religion and I never saw her in any sexual way nor felt attracted.
After the helicopter ride, she decided to go into a clothing store to take a look at some things. She took me along the bra and panties section while shopping for other clothes which made me really uncomfortable. She begged me to buy it since she felt too embarrassed to ask our parents. I said fine and told her to not mention that I bought it.
She had a pile of clothes she wanted to try on and the store had a changing room. I thought she would go in alone but my sister told me to come and help her try the clothes on. I was in complete shock and asked if she'd even be comfortable with that. She didn't mind so I went to the changing room.
At first, it wasn't too bad as she just tried on a shirt on top. But then she started to take off her shirt just in her bra. She also pulled her pants down to her panties and I was shocked. I had an instant arousal and tried to hide it but my sister saw the bump. I couldn't lie that I found her breasts and the curvature along her panties absolutely stunning. I apologized and told her to please forgive me.
She didn't seem to mind and then she told me to turn around for a second. She unhooked her bra and stripped down to no clothes at all and told me it's safe to look again. It was really hard and I didn't know what to say in a state of shock. I just complimented her nude body and just said she was gorgeous. I kept staring at her breasts and looked between her legs.
I said nothing as she put her underwear and bra on again and tried the rest of her outfits. We both left the changing room as I was in complete shock and I just bought her whatever she wanted.
After we left the store, I kept fantasizing about how I would have the best sex of my life with her. As she smiled, she leaned in to hug me and I hugged her back while looking into her eyes. I couldn't resist and gave her a kiss on the cheek and she said I might as well do a full on lip kiss if I liked her that much.
In public, I kissed her on the lips passionately and she reciprocated by engaging. Afterwards, I held her hands as we went into a coffee shop. We kept kissing and everyone in public assumed we were dating, which we unofficially were doing.
Later I asked if she would be my girlfriend and acknowledged it was awkward since we were biological siblings so she could decline.
She said she wanted me to be her boyfriend and we became a couple. We both made promises to let no one know about our relationship. On the train ride home, I became a lot more touchy feely as I pressed her breasts against me while hugging and slapped her butt for fun. She reciprocated by jokingly grabbing my penis. The second we came back to our neighborhood, we had to act normal so no one would know a thing. Later in the day around 11 PM, our parents went to sleep and I decided to just text her on Instagram and told her I was bored. She invited me to her room so I slowly crept inside and closed the door. I joined her under the covers and we giggled and kept kissing.
It became clear that we were escalating to something that we could not go back from. Our kissing became more passionate as she took off my shirt. I took her shirt and pants off and unhooked her bra. She lifted her legs up as I threw her panties across the room and she threw away my boxers. Our two completely nude bodies were under the blanket and we both just hugged tightly and could feel each other's body heat radiate.