I used this line on a girl once and it worked. She was one of those people who stops in on the street and hands you something and tries to introduce you to some product. Usually I don't stop and take those, but she was cute and I had been drinking. So she is going through the sales pitch she wants me to take the pamphlet.
I tell her that I don't really want the pamphlet, but I will take it if she gives me her number. She says "I would, but I don't have a pen or paper" (this was before smartphones). I didn't have my phone on me either, so I just said "It's okay, I'm autistic, just tell me what your number is and I will remember it"
Now, that doesn't make sense at all, but I made it sound like it did. The problem is that I'm not autistic and I had been drinking so a half an hour later I could not remember the number at all.
So anyway, just say whatever you want but say it like you mean it. And remember to always bring a pen