Choose Engineer.

Place a teleporter entrance against a wall.(If you don't put it against a wall than it won't teleport you.)

Walk back a few feet and place a teleporter exit. (Make sure that the way people exit is pointing at the entrance!) I know, I'm lazy for using the same picture.

Upgrade to level 3. (too lazy to put a picture.)

Start congaing towards the entrance. Once you get to it, it will teleport you to the exit, and since the exit is facing the entrance, you can just conga in a straight line infinitely.
Once your done, it should look something like this: Sorry if it's hard to see.