Reverse lap pillow, now that's an interesting move I've certainly never heard of.
So Kotori begins her assault on his defenses, sees a crack open up, says she's satisfied and leaves. I get that she's afraid of confessing and losing her flirty ambiguous relationship with him, but in case she forgot, she has a love rival to look out for.
Funny enough, I found this chapter on r/manga rather than MD itself, I didn't realize ch. 11 was at the bottom because all the other chapters have no volume number; the older chapters need to be reorganized into the correct volume numbers.