There is also a possible romantic relationship going on. Golf Ball said in "Take the Plunge: Part 2" that she only liked Tennis Ball in a platonic way (like siblings), after Coiny claimed that TB and GB had a crush on each other. In Lofty, they were fighting about whether the cloud looked like a golf ball or a tennis ball. However, this is the kind of thing siblings do. They still maintain their friendship in BFDIA, IDFB, and BFB. Tennis Ball also follows Golf Ball's instructions.
Episodes showing a friendship
- At Take the Plunge: Part 2 , Tennis Ball and his other teammates choose Golf Ball to be on his team.
- Insectophobe's Nightmare: Tennis Ball said to Rocky that he and Golf Ball are a duo. And both of them was seen tying their legs together.
- Half a Loaf is Better Than None: Tennis Ball is seen cheering for Golf Ball in the Loaf Contest.
- Zeeky Boogy Doog: When everybody is recovering everybody with the HPRC, Tennis Ball chose to recover Golf Ball.
- Every time Golf Ball manages her team, Tennis Ball is her assistant.
- At some point, they are just talking to close to each other.
- IDFB Intro: Golf Ball is once again close to Tennis Ball.
- Welcome Back: Tennis Ball and Golf Ball go together to the science museum of Yoyle City.
- Getting Teardrop to Talk: Tennis Ball helps Golf Ball find Leafy and Golf Ball lets Tennis Ball help her manage A Better Name Than That.
- Lick Your Way To Freedom: Tennis Ball tried to defend Golf Ball when 8-Ball replaced Golf Ball as team leader.
Episodes suggesting a conflict
- Take the Plunge: Part 2: When Golf Ball attempts to tell her team her plan, Tennis Ball, along with the rest of the team, ignores her.
- Insectophobe's Nightmare: Tennis Ball shouts at Golf Ball when she cannot walk in synchrony with him.
- Lofty: In the beginning of the episode, Tennis Ball and Golf Ball are arguing about the ball-shaped cloud.
- Insectophobe's Nightmare 3: When Golf Ball gets poisoned, Tennis Ball seems rather amused by the fact that she looks like miniature version of him.
- Today's Very Special Episode: Tennis Ball was also obeying 8-ball instead of Golf Ball, which doesn't connect due to him trying to defend 8-ball to not replace him. He even tried to prevent her from drawing their Four make-over.