I was 10. My older sis was 11.5, and my younger sis was 8. Like I said... my dad caught us and scolded us. He was really mad.
Although we were young.. we already know about sex because we used to look at dad's porn magazine whenever he forgot to lock the box where he kept them.
2 days later when I asked my older sis to show me again, and I showed her mine. I asked her if she want to touch it, and she did. But because both of us were standing, it was awkward. So, I told her to get down on her knee so she can do it better. At that time, I already know how to masturbate, because I used to play with some friends who are older than me. And they taught me how to masturbate.
So, my older sis gave me handjob for probably about 20 seconds. And I asked her if it is OK if I rub my dick on her face... She laughed, but she agreed. So, I rubbed my dick on her face.. and my dickhead touched her lips. But she closed her mouth. Next, I asked her to lick my shaft from the bottom to the top. And lick the head too.
I asked her to open her mouth, but she didn't want my dick to enter her mouth. So, I told her to close her teeth, but open her lips like an "O" letter. She did... so I inserted my dick and told her to close her lips. I started to move my dick and of course because of the teeth, my dick slipped to her inside cheek.
I don't know if it was instinct or because she got horny, but she ended up opening her mouth.. and allowed me to penetrate her mouth. But she didn't suck me. After a while, we stopped because we were scared that someone might caught us again. I didn't cum.
All of this happened probably around 3pm.
At night, I told my younger sis. She didn't believe me. So, I told her to ask our older sis.
The day after, my younger sis told me that she had asked our older sis, and our sis said that it was true.
So, I asked my younger sis if she want to do the same, and she said yes. So we did it. But it seems that my older sis didn't tell her the detail about how she refused to open her mouth at first...because when I asked my younger sis to open her mouth, she obliged. I even told her to suck it while my dick was in her mouth.. and she did it.
So, basically.. the first time my dick was in a girl's mouth... it was my older sis. She also my first HJ. But the first girl to give me BJ, was my younger sis.