Sleeping with my sister

(I'm 27, She's 21) It turns out that these days it has been raining too much in my city due to winter and the power has been constantly cut off because of Latin America. Well, yesterday the light went out at 1:00 pm and didn't come back on at night, and since the house was very dark my sister was scared, but slutty but scared, well it turned out she asked me to sleep with her in my bed, I agreed and everything was fine until then. I got into bed in boxers as always sleep regardless of the weather, she didn't have a problem with me sleeping like that, my sister got into bed wearing a flannel pajama, after some hours I was still reading something on my phone and my sister was still on her phone, but because of the cold she was still shivering, she asked me to go get some blankets, but I didn't want to and told her to go herself and neither did I want to go see due to the darkness and fear, I didn't want to go even with her phone's flashlight. After a few minutes I suggested something to my sister that I read on the internet, that sleeping naked increases human body heat, and if you sleep with another person equally naked they should hug and maintain body heat, she doubted it at first but then I searched for some articles and studies online and showed them to her, my sister finally agreed, I lit up the room with my phone's flashlight and she removed the top part of her pajama and I could see her breasts slightly, then she took off her pants and was left only in a pink underwear, she told me she didn't want to take it off, that she already had too much shame being naked next to me (but if you don't have shame, I thought), I told her it was okay and I proceeded to take off my boxers, got into bed and told her to snuggle up with me, she settled in and I could feel her body against mine, my penis pressed against her ass, and my arms embracing her and one of my hands lightly touching her breast, at first I felt her cold but over time I felt like she was warming up more we fell asleep and by dawn I could notice my penis had become erect but not as stuck to the butt of my sister when she woke up she thanked me for letting her sleep with me but got scared at night when she felt my erect penis hitting her butt she told me it was nothing and understood why the situation was like that. After years of seeing my sister naked in photos and jacking off several times I could be next to her and hug her naked body hope these power outages happen more often so something else can happen if you want to know more or ask you can write to DM