Joseph nearly swatted Rhys' bum to get him moving before he extracted himself from the Brujah's arms and into the tub. It was extremely fancy, with adjustable water jets and heaters to keep the water a comfortable temperature. He didn't use that feature much, as Kindred didn't notice temperature changes until they were extreme enough to cause tissue damage. But it was nice for his blood dolls after.
Most likely, Rhys just thought his body should hurt from the exertion. Kindred really didn't suffer muscle fatigue anymore. But he was only a few months out from being Embraced and still had to deal with his brain expecting such things from working that hard for an extended period of time. It would forget such things in a year or so.
Joseph was admiring the view as his long legged lover sprawled out in the tub. He settled on the edge splashing a little water at Rhys playfully before joining him. He was not remotely shy about his intentions, straddling his hips and bracing himself on the edge of the tube to keep from pushing Rhys' head under the water as he kissed him fiercely.