Not only do I think they do, I think archeologist Rui particularly enjoys bending his little chef over the counter and finger him while he complains about his freshly made dinner getting cold between moans. I think whenever Rui gets back home from exploring and finds Tsukasa waiting for him all smiley and pretty he cannot help but throw himself at him and nom at him. I think foodplay would be nice for them for obvious reasons… also because this chef is so stingy with the way his food is presented but Rui can only eat whipping cream if it's served right on top of Tsukasa’s nipples, he would also complain when there isn’t any milk coming out of them. I think they should fuck and then later realize that the whole kitchen is on fire. Good riddance d(d´∀`◎)