Don't scare away the nice people, Anny.
Well, they interact by... okay, let's do a small sample:
First Person writes this: 'Bob was walking down the street, just minding his own business, when suddenly he tripped over a rock! Stupid rock... he thought grumpily, getting up and brushing his hands off on his trousers. But he wasn't looking and he bumped into someone and fell back down.
"Oh, I'm so sorry!" he said quickly, jumping to his feet and feeling terrible about running into the person.'
Second Person writes this: 'Anny hadn't had a good day. She had broken up with her boyfriend, dropped ice cream on her lap, tripped and fell right into a pond, and her shower at home refused to run anything but icy cold water. "Well today sucks..." she muttered, kicking a small pebble. She was looking down and didn't notice the man until it was too late. Luckily she had balance, and she managed to catch herself before she fell, but the man didn't.
Giggling at how funny he looked, Anny shook her head, "Oh, don't worry about it, I'm fine." she said with a small smile.'
Aaaand that's basically how a regular RP would go. Except with a different plot, your own characters, and more interesting things going on. :3 And that was just really simple stuff, we expect a little more mature writing, not just 'he walked over there. He sat down. He ate food. He was happy.'