Ponnie

Ponnie is the Non-binary ship between Pearl and Connie Maheswaran from the Steven Universe (Fandom) fandom.

Canon
Pearl and Connie first meet at the end of "Bubble Buddies". But when Pearl tries to introduce herself, Garnet stops her by saying not to mess with Steven's "funky flow".

In "Fusion Cuisine" it initially seems that Pearl is going to be chosen to attend a dinner to meet Connie's parents. But Pearl's aversion to eating food results in high jinks when Alexandrite (the fusion of Pearl, Amythest and Garnet) is chosen instead.

In "Alone Together" Pearl is shocked and surprised to see the Steven had been able to fuse with Connie to become Stevonnie. Pearl initially thought the fusion between a gem and a human as 'unprecedented', 'impossible', 'or at the very least inappropriate'. Insisting the two should unfuse immediately, though Pearl would quickly grow out of this mindset.

In "Full Disclosure" Pearl tells Connie, 'I don't understand your human relationships.'

Since "Sworn to the Sword" Connie convinced Pearl to teach her sword fighting by appearing very passionate and devoted to staying by the side of Steven and the Crystal Gems in protecting Earth. This struck a chord with Pearl and moved her to the point of tears, with this resulting in her strict and rigorous training of Connie. Pearl takes them to the "Ancient Sky Arena" for training and explains the history and significance of this place. She hands Connie a sword and explains the concept of being a knight and that Connie is nothing more than a protector. The two share a mutually respectful mentor-student relationship, in which Connie starts to call Pearl as "Ma'am". Pearl tells Connie to bow then proceeds to summon a "Holo-Pearl", which Connie thinks is cool. Pearl instructs onnie on the correct stance while singing "Do It for Her". Connie's greatly improves her sword-fighting ability, but Pearl's emphasis on self-sacrifice and self-denial durring training causes Steven to grow concerned. Steven interferes, leading to Pearl having a breakdown. Connie and Steven comfort Pearl, after a heartfelt conversation, she calms down and comes around to a more lenient viewpoint.

In "Nightmare Hospital" Connie displays the results of her sword training under Pearl when a "Cluster Gem" attacks the hospital.

At "Steven's Birthday" Pearl and Connie are a team together, playing badminton against Steven and Amethyst.

In "Gem Hunt" Connie goes on her first official mission alongside Pearl and Steven. Pearl shows great pride in her pupil's performance.

In "Crack the Whip" Pearl is unable to attend a training session with Connie, due to needing to go on a missing with Garnet to track down Jasper. Connie understands, realizing the importance of the mission. Amythest volinteers to instruct training insteed resulting in Connie to be critical of her unorthodox methods.

In "Buddy's Book" Connie learns more about Pearl's and the Crystal Gems' history, when she and Steven find "Buddy Buddwick's Journal'.

In "Mindful Education" Pearl and Garnet instuct a special training session to help strengthen the fusion between Connie and Steven.

In "The New Crystal Gems" durring the absence of Pearl and the other members of the Crystal Gems, Connie, Peridot, Lapis and Pumpkin substitute in forming "The Crystal Temps".

In "I Am My Mom" Pearl joins the effert to rescue Connie and the other kidnapped humans from Aquamarine. While the rescue of Connie is successful it ends in the capture of Steven and Lars.

Fanon
Ponnie is a somewhat niche but relatively popular ship within the fandom. Sporting numerous fanfics and fanart, both SFW and NSFW. A common theme within the fandom is the "College AU", which normally sees Connie aged up and attending college, with Pearl being a residential professor.

Fandom
Shipping between Pearl and Connie primarily stems from their dynamic in the episode "Sworn to the Sword". In which the two begin a Student/ Teacher relationship, as Pearl instructs Connie in the art of swordfighting. Resulting in the platonic, mutual respect such relationship entails.

This coupling can often be considered as a controversial pair within the fan base, much like other ships with a similar dynamic.

Inturn this has lead to some fans to view this pair as a one-sided "Hot for Teacher" type ship, with Connie having an unrequited crush on her mentor Pearl. Alternatively some fans have viewed the ship in the reverse as a "Hot for Student" type ship, with Pearl pining after her protégé. Aditionally there are fans who will "Age-Up" Connie and hold this pair as a "Mutual Attraction" ship for fun.