Serph's perplexed frown remains pasted on his face as his confusion only deepens. He's not sure why Jack thinks he (and John??) want to have sex again. That was just the result of the moon warp and the confusing whirl of impulses from almost dying from John drowning him and his demon's renewed hunger upon being brought back from the brink by John, wasn't it?

...Wasn't it?

Maybe he should ask John. Even if he's not human, maybe he'd have some idea of why Jack thinks that. Or what Jack means by in whatever form that happens.

"There's nothing to arrange." He's sure of it. His rests his other hand on top of Jack's. "We won't be distracted again."

Now that he has some idea of the cause, then it's a simple matter of taking precautions. It's just like when he first gained his demon. He'd been taken off guard by the roaring hunger, but the next time he maintained control.