A surprising number of these exist, despite the setting of the story.
When Maou presents a scroll to Hero saying it's an economic analysis, Hero stares at her blankly and Maou gets annoyed that he doesn't know what that means.
Maou's constant attempts to touch Hero during their first meeting.
Towards the end of episode one, just as she is about to depart on her journey with the Hero, Maou grabs the horns on her head and pulls them off, revealing them to be part of a headband. The Heroʻs subsequent reaction is priceless.
When Hero and Maou first arrive at the village, Head Maid runs out to greet them... calling "Maou-sama" repeatedly at the top of her lungs.
The reactions of the students when either Hero or Lady Knight does something over the top while training them.
At the end of the first episode, Maou touches a lamp that shows a person's memories by accident, revealing that she tried practicing hugging and kissing Hero with a dakimakura with Hero's likeness drawn on it, and eventually tackling it to the ground and rolling while still glomping it. She immediately asks Hero to wipe it from his memories.
Episode 4 shows that she still has it and uses it like a security blanket when she sleeps.
In episode 4, Hero's Chick Magnet status is played for all its worth, with Head Maid listing off his most recent escapades as the Dark Knight: getting mobbed by harpies when staying at an inn, accompanied by an image of the Hero in his very badass Dark Knight armor cowering in the fetal position; getting confessed to by the translucent blob girl, accompanied by the image of the Dark Knight helplessly floating inside of a see-through Blob Monster; and having the Cow Girl claim him as her betrothed, accompanied by an image of the Dark Knight getting crushed under her enormous breasts, which are more than twice as big than both her body and the Hero's body put together.
In episode 7, Demon King and Lady Knight lay on either side of Hero and pet his hair. It's his silently embarrassed expression that sells it.
Hero's hair is all fluffy.
In a later flashback, it's revealed that she'd been hoping to touch his fluffy hair since before she became the Demon King.
Episode 12. Maou reappears in front of her subjects after having been away for 2 years. She introduces Hero to them disguised as the Dark Knight, while he does some sword swings. Her subjects just have a blank look on their faces, and Head Maid tells him to be more flashier. Cue an AOE spell, and the top of a mountain melting off.
Dark Knight: Whoops. Overdid it. *crowd goes wild*
The stunned look on Maou's face sells it.
Lady Knight tells Maou that she gave "it" to Hero. Maou gets angry... until Lady Knight clarifies that she gave her sword to Hero, not her body.
During the end credits, Maou and Lady Knight get into an argument and squash Hero between their breasts.
In the Comp Ace Manga version of the plot line where Maou gets taken over the spirits of the previous dark lords after all is said and done and Maou is returned to her normal self Hero is treated to a view of Maou's naked body (of course the reader doesn't get to see the goods as by the time we see Maou she's already covering herself) to both of their utterly hilarious and cute embarrassed and flustered reactions to it.