You were on the train standing up because there were no seats left. When the train stopped at a station, you fell on somebody's lap.

"Hm?" the guy says, looking at you

"Oh, I'm so sorry! I just fell, I'm sorry." You were about to get up when he stopped you by holding your waist

"No, it's okay. You can sit here. I don't mind." He says while still looking at you while smiling