Fabrizio done as he was told, working with his tongue on the cock only to flinch when he was scratched like that, it hurting a little bit. Still there was some nice gesture following it so he relaxed soon after, putting a stop to wondering if there was something he did wrong to deserve that. There wasn't much time he had to prepare but little he knew (unable to notice the energy flow in such a situation) that the mage used a spell to relax his throat so it wouldn't get utterly destroyed by something so big pushing inside. So as the impossibly big thing moved inside his throat, bulging it and stretching, there was no pain although the little mouse could feel every inch going inside of him, it blocking the air flow, his throat sealed perfectly. Still he didn't fight, his cock twitching in his sister's mouth. Soon he was able to take in a breath or two before being filled with a cock once again, first time in his short life being filled up so utterly, the hard tip feeling like it was able to touch his stomach. Moaning softly Fabrizio felt a deep excitement raise inside him, utterly ashamed of it as his back doors twitched around the mage's cock.