I could see her possibly getting even more worked up about it than the average romance FMC because of how canines are about territory. She might start to realize that she seess the MC as her “territory” and get extra defensive, which would be greatOhohohohohoho....
People are already getting worked up over this succubus taking an interest in our MC, but where people see an instigating thot, I see a much-needed kickstart. After all, what better incentive for Tsumiki to start acknowledging her feelings than the idea of someone stepping on on what's 'hers'?
All the better that Tsumiki and the succubus appear to know each other. I say bring it on, I'm grabbing the popcorn.