Yeah, same here, I'm trying to figure out where to put the damn goldfish. Part of my current assumption is that you need to get outside but I thusly have been incapable. I have no idea what the game wants me to do here.
Btw, kinda funny thing you can do, you can keep unlocking the drawer and keep "obtaining" the useless space knife.
EDIT: It's really stupid, but seduce the cup. That's how you get them to 'suck' it down. What a non-trivial amount of effort all because of a pun.