Answer:
When I get closer my tail grows longer, but when I go away my tail leads the way.
My first master has four legs, my second master has two. My first I serve in life, my second I serve in death. Tough I am, yet soft beside. Against ladies cheeks I often reside.
In Paris but not in France, the thinnest of its siblings.
Put into a pit, locked beneath a grate, guarded through the night, yet it still goes out.
I drift forever with the current down these long canals theyβve made, Tame, yet wild, I run elusive Multitasking to your aid. Before I came, the world was darker, colder, sometimes, rougher, true. But though I might make living easy, Iβm good at killing people too.
I am rarely touched but often held. If you are smart you'll use me well. What am I?