Somehow, he manages to keep from literally draining Cassidy dry, eventually releasing him and resting his head on the other vampire's stomach, enjoying the after-effects as well.

It might be possible that Eccarius had a better time than Cassidy, although one wouldn't know it based on their respective reactions; Eccarius' being quite a bit more understated. But then, drinking vampire blood—especially old vampire blood—is a different sort of feeling, in Eccarius' opinion. Fantastic as it is, it's not exactly orgasmic; considering his own still-swollen dick is rather uncomfortable at the moment, still confined in those ever-so-tight leather pants.