The only seiyuu connection I get here is that Tokitsu and Yuki are both voiced by Fujita Saki. I think it's parodying something, but I don't know what it could be.
Actually what I meant was Mamiya's. because the artist going all the way through to mention her Voice Actress, so I thought there must be some reference.
artist commentary on twitter:
羽川さんの声で読んでね
translated as "Read in Hanekawa's voice". I googled it and I think it was hanekawa_tsubasa from bakemonogatari. I don't watch it, so I don't know what scene she's parody-ing.
...the end of...Home-made cakeHAH!...Akebono-chan's punishmentOh my.It's to celebrate...Is it someone's birthday? How nice!
Sure thing!Mamiya-san, teach us a cake recipeTeach us~Was that a pun!?
CV. Yui Horie
"Sentence" is "keiki" in Japanese. Cake is "keeki" in Japanese.