Analysis of Unwelcome Guest

You wake and I'm with you.
You wash and I watch you.
You work with me in you.
You feed while I eat you.
I'm your silent companion
And you can't shake me off.
I'm your stow away passenger,
Your unwelcome guest

Where love lives I lurk near it.
Where blood flows I ride with it.
Where life starts I pollute it.
Where lust grows I thrive on it.
I'm your sleeper agent,
Your terrorist cell.
I'm your hidden agenda
And nobody can tell.

Hush don't talk of my presence.
Hush don't say I exist.
Hush don't mention I live here.
Hush, our secret must persist.
If he knows he'll reject you
And he'll tell the whole world.
If they know they'll all judge you
Your reputation unfurled.

When you touch him I'm crawling.
When you kiss him I'm walking.
When you taste him I'm running.
When you hold him I'm sprinting.
And you lie next to him now
Just a casual encounter.
And I lie within him now
His new lifelong spectator.

So accept me, be a good keeper
So embrace my affliction
So endure me, hide me deeper
So conceal my contagion
Because I'm with you for life now
If that's what you call it.
I'm your poison and strife now
And you had best not ignore it.