This is the latest fic posted at
nextgendarkfest.
It's NC-17 and written to the prompt:
Slash #9 - The boys make a bet as to who can first seduce the other one's father. Scorpius fails, but lies about it, Albus succeeds by greatly regrets it. What impact does this have on their friendship and their relationships with their fathers?
You can read it
here.