Say you're going to the store to get some milk! Or maybe sneak out at night?
That reminds me of back when I was in highschool, I ended up at a friends house for a party and her friend from another school was there and she was all over me for some reason (reason being she was drunk most likely), but then my mom made me come home because it was 6. She was even hot too. And I'm not just saying that out of desperation, she was actually hot.
I count it as the first and last time I'll ever be actually close to having sex, so it's a pretty significant memory.