That was rather the reason Joseph was doing it. Well, besides the fact it was titillating and fun. He enjoyed introducing Rhys to new things and seeing how he reacted.
Joseph let out a pleased growl as Rhys grabbed his hair and demanded he lift his head. He was certain to take his time licking the bite marks closed before he straightened. He didn't let up stroking the younger Kindred's cock. "What, love?" he encouraged.