It is the last time he'll make it because he is very much realizing the (very exciting) danger he's in. Lucifer getting to explore a very willing lover for the first time? Just because Istredd's more experienced doesn't mean Lucifer can't catch up quickly.

Istredd's body is already flushed with arousal and he whines a little, trying to move toward Lucifer to get that graze. I should have tormented you. He gave in too quickly, but he was so eager. This is so bad (good) for him. Istredd is not too proud to beg, which he's already proven, but he makes eye contact.

"Please, Lucifer."