You make up your own rules, just like me. Portal 2 Sounds | GLaDOS: Don't do it.
(It's the series of chambers that grants a player the "Professor Portal" achievement if you have done it but your partner hasn't.)

"Pull me out pull me out pull me out pull me out Leave me in leave me in." SPAAACCCCCE! [low-pitched 'space' voice] Yes.

[low-pitched 'space' voice] I'm proud of you, son. I like your style. [normal voice] Dad, are you space? Dad! As per the title, fired up coop on Portal 2 after a long time (new partner) and was stuck in the opening section of the initial chamber where it requires you to wave at your partner. Now we are a family again. BECAUSE I'M A POTATO. I'm in space! Ha! "Don't Do It - Portal 2" is a high quality rip of "Don't Do It" from Portal 2.