If you had a portal gun. What would you do with it.

I'd send Justin Bieber to my house.

Your turn SP.

I'd send Justin Bieber to your house too... Just get him out of my country...

And these:

 Spoiler

I would use it to punch people in the throat through the internet.

Kill retards.

1. Place one portal above me
2. place one portal below me
3.fall perpetually
4.????
5.PROFIT

drug trafficking and stuff of the sort.

I'd shoot a person with it to see what would happen.

Yep... definitely all of those.