I may be wrong, but I think Lucaon is jealous or has the tendency to get jealous when it concerns Logan, the new servant. My reason for saying this is because Kyon is concerned about others finding out about their relationship. Especially Logan because of how sharp Logan is. For example this chapter regarding Lucaon's shirt. Logan could easily put the pieces together and figure out their relationship and that is what is making Kyon anxious and concerned. Which is why he told Lucaon to be careful where they have sex. And it seems Lucaon knows this because in this chapter he asked Kyon why he wasn't as awkward when they were caught by Ryan. Just imagine Kyon's reaction if the person to enter was Logan and not Ryan. I know for a fact he would have had a completely different reaction if that were the case.
I may be wrong, but I think Lucaon is jealous or has the tendency to get jealous when it concerns Logan, the new servant. My reason for saying this is because Kyon is concerned about others finding out about their relationship. Especially Logan because of how sharp Logan is. For example this chapter regarding Lucaon's shirt. Logan could easily put the pieces together and figure out their relationship and that is what is making Kyon anxious and concerned. Which is why he told Lucaon to be careful where they have sex. And it seems Lucaon knows this because in this chapter he asked Kyon why he wasn't as awkward when they were caught by Ryan. Just imagine Kyon's reaction if the person to enter was Logan and not Ryan. I know for a fact he would have had a completely different reaction if that were the case.