Based on Sonnet XXIX, by Shakespeare

When I deplore my fortune as a spy,
And all alone beweep my outcast state,
I take revenge and make my students cry.
I look upon myself and curse my fate,
Wishing that I'd been placed in Gryffindor,
Wanting to be like thee, with friends possessed,
With Seeker skills, bright emerald eyes, and more,
A Magic purer than a Virgin's breast.
Yet in these thoughts myself almost despising
I realise that I mistook for hate
(As, in the sky, the Darkest Mark arising,
It seems to tear me) a more mysterious fate.
Though thy sweet love will be perhaps my doom,
I'm happy when I'm riding on thy broom.

Dom!Snape Sonnet

O foolish boy, your heart is on your sleeve;
You wonder if I dream of you at night.
What would you want to see in my pensieve?
This path you're seeking takes you from the light.
It makes me feel so powerful: you kneel
And suck my cock as if you were my slave,
Your mouth so warm and wet is all I feel,
Your lips and tongue on me are all I crave.
Lick every inch, suck every drop, my pet;
In chains I'll bind you, shackles round your hands;
My whip is sharp, and all the pain you get
Will make you squirm beneath the leather bands.
To hear you say that you are mine is bliss,
And your surrender's sweeter than your kiss.