I think Marie's punchline is referring back to what Osakabe-hime says in the first panel, specifically the term 百合談義 (yuri dangi). Is this an idiom? Neither "lesbian discussion" nor literal "lily discussion" seem to make sense in context.
Hime really shook the hornet's nest by pretending to hit on Kadoc here.
this...that...Let's discuss the occupation of my kotatsu, what are your thoughts?T-talk to someone else about this, please...I'm talking to you because there's no one else, so listen up.Why's he looking so skittish...?It can't be, is he being shy with me...?He's not used to talking to girls....!?umm...Hey, hey, chat more with this princess~Turn your face my way. Why's your face red?Hey, hey, Ma-chan.I-I am not your Ma-chan...HE'S MY MA-CHAN!!Seems like the stray servant from pan-human history needs to learn her place!You got guts for putting my Kadoc in this segment!T-that wasn't the case at all, please forgive me!They like the same guy...That's yuri.GEEEEEHHHH