Answer:
You throw me out when you want to use me and you take me in when you don't want to use me. Who am I?
A hole leading in, a hole leading out, we connect to a cavern that is slimy all throughout. What are we?
I'm not really more than holes tied to more holes. I'm strong as good steel, though not as stiff as a pole.
Twigs and spheres and poles and plates. Join and bind to reason make.
Round like a dishpan and smaller than a bathtub. But the ocean can't fill it. What is it?
If itβs information you seek, come and see me. If itβs pairs of letters you need, I have consecutively three. What am I?