The Adventures of Tsunderegg

Main characters here are Senpan, Tsunderegg, and Yandere Spatula. This piece is imitating school life animes with some weird love triangle.

The stuff happening in the picture:

Senpan has just confessed their love for Tsunderegg. Tsunderegg is feeling flustered while Yandere Spatula looks on from the window feeling increasing anger towards Tsunderegg as they want Senpan for themselves. 

Explanations I found for some of the words.

Yandere: Yandere is a portmanteau of two Japanese words. The first is yanderu, which means “to be sick,” and the second is deredere, used here for “lovestruck.” A yandere is often sweet, caring, and innocent before switching into someone who displays an extreme, often violent or psychotic, level of devotion to a love interest.

Tsundere: A tsundere is a character, most often female and in anime, who switches from being tough and cold towards a love interest into being soft and sweet.

Senpan but I made it a play on words of Senpai: A Japanese honorific used when someone is older than you in age or they have more experience in a field than you.