I think the kinky use of the imperius curse is CRIMINALLY underrepresented in the harry potter fandom as a whole so let's fix that

Maybe Credence is failing at finding the child, or he's just become so exhausted and downtrodden that he's about to give up entirely, and Mr. Graves asks him if he'd like some help

To which Credence says yes and Graves puts his wand to Credence's temple and murmurs 'imperio'

And then Credence experiences sheer bliss, loves how good it feels to submit and obey and not have to think for himself

Only sometimes he wakes up for a few brief minutes and...something's not right. He's not looking for the child he's touching himself, and Mr. Graves is watching. He's wearing silky lingerie and he doesn't remember putting it on. He's tasting Graves' come and swallowing it down but how did he get onto his knees? And then Graves notices that Credence has accidentally snapped out of it and puts him back under again. Wash rinse repeat.

/Brain/wash, rinse, repeat, if you'll pardon the terrible pun, until Credence is the perfect mindless slave~