Dogs can’t operate MRI machines, but . . .

No hands I have, yet still I press, In moments thick with expectation’s stress.

Used to sign your name with, usually blue or black, Or sprayed out by a squid in a defensive attack, It used to be found dripping off the ends of quills, Or hiding under stoppers in the shallowest of wells

I top your latte, crown the sea, and cushion you while you sleep peacefully.

My first word is an age based on metal, an integral part of steel, not simply carbon. My second helps your breathing stay, without them, you would be done. All together, I keep you alive, stuck in a machine, as pressure pulls air inside.