You're a late bloomer at nine sweeps, and you don't yet have a concupiscent quadrant filled. This leaves you alone and self-pailing for the duration of your mating cycle—at least, that was the idea. When Karkat bursts in on you, it sort of throws off your plans for the week.

Bacchus says the Percy and Jason having sex will be a suitable sacrifice to get him to help them defeat the giant twins. These two fics show two different scenarios for how that could play out.