9/Rose run into 6 while at a wedding.
"So who are we meeting again?" Rose asked as they worked their way through the crowd.
"Sir Nolan Harrison," the Doctor replied. "He saved my life once, and invited me to his wedding. I guess the TARDIS decided that it was time for me to come." He paused. "I could have sworn that I came, though..."
Rose grinned. "Well, you did promise to take me dancing."
He pulled her tighter. "Though we did that last night," he smirked.
She swatted his chest. "Literal dancing, you randy old alien."
The Doctor chuckled and returned to looking for his old friend. "Why don't you go mingle? It might take me a while, and I don't want you getting bored."
"Oh, I dunno," Rose said as she discreetly groped his bum. "There's some good things here."
He rolled his eyes. "Minx. Go dance with some pretty boy before I get my hands on you and you lose your chance."
She pressed a kiss to his cheek. "You're the only pretty boy I'm interested in," Rose said, but left to join a group of women by the buffet table.
After watching her go with a fond smile, he once more searched for his old acquaintance and his new wife. Eventually he found them through a gap in the crowd, but before he could reach them a curly-haired man wearing a bright patchwork coat cut him off.
The Doctor groaned. "Oh, no. What are you doing here?"
His past self frowned. "What am I doing here? What are you doing here! I was actually the body to meet him, you know."
"My TARDIS insisted that I be here," He replied. "And since I don't remember coming here something clearly happens to make you forget. I'd rather not stick around to see what that is."
His other self made to reply, but Rose arrived, wrapping her arms around him. "Did you find your friend?" She asked, then blinked at his other self. "Oh, hello. You're the Doctor too, aren't you?"
"How'd you know that?" He asked.
"He showed me pictures," Rose said vaguely. She turned to her Doctor. "Look, remember that Grobrowski we ran into? He's, er, here. And I think he ate one of the bridesmaids."
The Doctor closed his eyes. "Is he purple?"
"No, green."
His past self looked annoyed. "Oh, dear. He's been feeding on the guests." Then a look of concern flitted across his features. "But all the known Grobrowski's are imprisoned on their home planet. How did they get past the Time Lord's defenses...?"
"And this is why I'm going to have to erase my memories," the Doctor said grimly. "Trust me when I say I have to handle this. You're experiencing your own future now, and there are things you cannot learn."
Rose looked at him in concern. "Doctor?"
He pressed a kiss to her forehead, ignoring his older self's disturbed expression. "Rose, stay here. After what happened last time I can't risk it. Make sure everyone in here stays calm, and if anyone tries to leave don't let them, understand?"
She nodded solemnly. "Be careful."
He left, and Rose immediately began digging through the hidden pockets of her dress. "Right. Do you know if there's another way out of here?"
The blonde Doctor raised an eyebrow. "You're going after him, aren't you?"
She snorted. "Course I am. He nearly regenerated last time, and he's not running off without me. Come with me if you want, but I'm not leaving him."
Looking down at her determined features, the Doctor knew it would be useless to argue. "We'll use the staff entrance. They won't suspect anyone using it."
She nodded. "Perfect. But you better keep up if you want to help!"