Right off the bat in episode 1, we get this speech from Rinko: "Every night I'd stare at the sky, waiting for a Prince Charming to come pick me up. Then I get this clumsy rabbit (Ruby), which is certainly not what I'd expected." That's right, she's comparing Ruby to a Prince Charming. SUBTLE.
Sara seems to have it really bad for Akari. The amount of times she blushes around her is ridiculous. To say nothing of that time Sara saw Akari in a wedding dress (like she's just got enlightened), or Akari spoonfeeding her, or how they intertwine their fingers whenever they perform a spell together... And in the semi-finals of the Jewel Star Grand Prix, Sara clearly felt jealous of Miria getting to fight Akari and expressing her feelings about their friendship.
Sara: It's not fair...
The OVA is packed with this between Akari and Alma. Akari is constantly touching Alma's hands or locking arms with her. Alma is extremely protective of Akari and near threatens anyone who she thinks is badmouthing her. Unfortunately, this doesn't make her the most approachable person, so she tries to shut herself off from other people. And she tells this to Akari:
Alma: All I need in this world is mother, Yuuma and you!
Later, when Akari tries to cheer Alma up, there's this scene where their faces are sooo close, you honestly think they're about to kiss. The constant blushing is not helping their case. And to add to all this glory, Yuuma has very little to do in this OVA. Akari is more all over Alma than him.
Even Kanon and Ruby get this at times. One of their Cat Fights actually ended with Ruby on top of her, sobbing into her chest.
In episode 20, Kanon launches into a heartfelt, almost romantic speech when she thinks Ruby is coming to save her from prison, Love Bubbles and all.
In the first version of the opening, their actions mirror the lyrics quite closely ("I called out to you, but you gave me no reaction" "I wonder if you've noticed? I'm next to you"). Now remember that "GO! GO! Sunshine" is a love song.
Their classmates sometimes have... interesting things to say about them when they see them fighting: "they seem to be having fun", "they sure get along" and, once, even "they love each other!". And none of this was in sarcasm.
In one episode, Ruby feels up Kanon's chest. Context: Ruby has turned into a baby and needs milk.
Hinata and Peridot are perhaps the closest roommates in the show. Peridot frequently pushes Hinata to become a stronger person (and the results show), and in episode 7, Hinata seemed all too sastified with being at Peridot's beck and call and spoonfeeding her.
In the episode where the story of Shouko's gang's formation is revealed, Charotte can be interpreted as being Tsundere for Shouko.
Charotte develops a crush on a mosquito named Katori. Because Katori sucks blood, she is in fact female, though only Sapphie seems aware of the fact. While Charotte can be written off as simply not being aware, it still raises a few questions about Katori.
When Ruby, Kanon and Peridot are begging Hinata to let them copy her homework, at some point they whip up bouquets of roses and look as if they are proposing to her for marriage, making Hinata blush. This is even lampshaded by the narrator.
In the episode where Shouko starts working in Master's cafe, she punches anyone coming through the door, including Hinata, who conveniently lands on her chest.
Angela and Flora become remarkably close shortly after meeting for the first time, nuzzling a lot of the time. Oh, and that first encounter consisted largely of them gazing intensely at each other and blushing.
Kaede and Komachi, Kanon's Girl Posse, reenact how Kanon's and Mikage's relationship should be going, which is kicked Up to Eleven when Kaede passionately holds and looks as if she's about to kiss Komachi.
Kaede: I could cover you in kisses!
Waniyama seems to be quite admiring of strong men and once hit on Masago.
In episode 25, everyone seems to be dating someone, prompting Labra to proclaim that Angela is her girlfriend. Cue an embarrassed Hinata explaining to her that that wasn't possible, because they were friends already (note that she didn't say "Because you're both girls.").
Coal's crossdressing makes this inevitable. It gets better with Io liking his crossdressed form until the upsetting reveal.
Episode 2. Ruby's expression when first meeting Pink is the same as Garnet meeting Blue Knight. When Angela tries to arrest the KiraDeco 5, Ruby jumps to tackle her out of the way and saves her, even though they've just met. Then the secondary effects of Angela's spell make Pink fall asleep, and Ruby is all like "YOU GONNA GET RAPED". The next morning, Pink is sleeping on Ruby's bed with Ruby on top of her. Then, Ruby packs up the decorative stones she loves so much and gives them to Labra as bail to get them off Pink's case.
In episode 3, there's a scene where Pink seems to try to tenderly touch Ruby's facenote (actually, she was going for her eyes), and then immediately backs away with a flustered look on her face.
In episode 20, Ruby and Pink are directly compared to Garnet and Blue Knight when Pink promises to protect Ruby from Garnet's assailant. One time, Pink performs a Diving Save, and is looking all heroic while Ruby looks at her with loving eyes saying "Oh, Pink...", with Love Bubbles in the background.
In episode 24, Pink gets upset at the fact that Ruby has a date to the ball, as she was hoping that Ruby would be her date. Her reaction at discovering Ruby's boyfriend can be read as jealousy.
In episode 34, Ruby looks distressed when Pink is about to ring the Amore Bell (if you ring the bell with someone you love, you'll stay with them forever) with Gray.
In episode 36, Ruby sees Blue carrying Garnet and asks Pink to do the same with her while blushing.
At the start of episode 33, Pink distracts Ruby by telling her that Opal is flying around "butt-naked". Ruby turns to look with stars in her eyes.
In episode 38, Retsu receives "get hugged by Blue" coupons by mistake. "Now, Blue! Hug me as hard as you can!"
In episode 44, Kohaku pleads with Tour not to "partner" with Sapphie (whom Tour was trying to seduce), saying that Tour's real partner is him. Tour is moved, instantly drops his Latin Lover persona and holds hands with Kohaku while re-asserting their partnership.
In episode 25, the gang puts on a play, and Sapphie and Ruby play the prince and princess, respectively. A highlight is when Sapphie pulls a Bishōnen face and makes a heroic pose while beckoning for Ruby's (who's lying on the floor in typical Damsel in Distress fashion) hand.
The OP has Mizuki and Karon taking cream from Momona's face and licking it.
And the ED has a sequence where Lilian replaces Momona's Love Interest's position, flustering Momona in the process.