((Some of my favorite headcanons!!))
Eridan's ear fins wiggle around when he is really happy, and it embarrasses him.
Sollux knows this and tries to make it happen, but has only succeeded twice.
Sollux never uses his psionics around Mituna.
One of the reasons Sollux likes red and blue so much, is because they make purple.
Sollux forgets to eat a lot. Karkat usually cooks him food.
When Sollux gets really happy, he buzzes.
When Sollux got a terrible migraine, he stayed off coding hacking and trollian for a few days.
Feferi had Eridan go and see if he was okay. Being Highbloods are cooler and Sollux was ridiculously hot, Eridan held him to cool him off.
Neither of them speak about it.
Eridan likes to steal Sollux's socks.
Sollux likes to seatl Eridan's scarves.
They both secretly think that its cute (not that they would admit it)
He would never admit it, but Sollux was very insecure about his eyes being mis-matched
Sollux would actually find being dominated very exciting.
Once, Eridan beat Sollux at a game. He has never let Sollux live it down.
Sollux's favorite pick up line is: "2 ii2 better then one- your 2iingal, we could make a double."
Sollux can't swim