Contraction of "pr0n" and the french word "poney" (pony).
Can be used as an adjective either to describe small horses having sexual intercourse, or something that seems cute but you find disturbing.
Two people are in a barn :
"- Hey look, these two ponies are getting laid !
- Gross !! Dude, you know I hate pr0ney !"
"- Hey Barry, see how my kitty licks itself. He's SOOOO cute when he does that !
- Mhhh, that's kinda pr0ney though..."