Having Kai feed from him was familiar, and reassuring in its own way, to Rurik. His strength was such that he could withstand the blood loss, even on a regular basis. He had no concern for his health, as it were, if Kai went too far, and past the point of Rurik fighting him off, so be it. Rurik doubted that would happen, in any case, and trusted Kai fully.
As the blood flowed from his veins, throbbing mercilessly at the point where Kai suckled, Rurik let his mind drift to recall the softness of Kai's touch in other intimate positions. He still struggled with the concept, his sexuality having been effectively beaten out of him in his younger years, but again, with Kai, the trust was unyeilding.
He found his hand had moved to gently caress the curve of Kai's hip, suggestive of his thoughts.