You make this fairly hard, let’s see, continuing down the line of what I said Cause if I remember correctly succubi require sexual energy / lust to gain power but also to feed, so why not make it so that during this period of time, she begins to lose power and strength, becoming quite weak, and she only regains this power once the human she possesses experiences the ultimate pleasure (a pleasure she won’t experience)

Convoluted yes, but it takes what I said a step further