My gf at the time was 18 and her sister 21 and their pretty close (actually so close that my gf tells her everything about our sex life and stuff)
We met at her sisters house to drink together and celebrate her sisters raise at her job
So we turn the TV on, put on some playlist on YouTube and start drinking and having a good time
After some time we all are a bit light headed and the girls show each other some pics on their phones
My gf goes through her sisters phone and accidentally sees a nude of her and gasp loud and says “I’m so sorry”
Her sister says “it’s no problem you can loot at them if you want haha”
Her sister opens her nude folder in her phone and shows it to my gf and my gf does the same for her
I try to not be a total weirdo and try to not look on her sisters phone in my gf’s hand
Her sister see’s that and says “you can look if that’s okay for her”
My gf nods and smiles