Throwing my hat into the ring... null!spam has ticklish wings that make him shriek, and Tenna uses that to his advantage when he's annoyed at him. His back is sensitive to gentle tickles, especially around his shoulders
You know how null!tenna's antennas have that amplifier? That itself is ticklish, and his antenna are more ticklish than the OG's antennas to the point that just scratching your finger along them can make him buckle.
And I think both of them are feather sensitive too, just cuz. Mettaton uses it against both of them all the time. But he's gotten revenge tickles a lot too so it balances out. (Nulldragonhere)
Oh, yes! Yes to all of these. I love your ideas.
"Hey!" Tenna growled in warning as he struggled to keep his laugh in while Spamton gently scratched his antenna as he tried to get away from his hands, "St-stop tha--hehe!"
"Not until you [stay calm]!" Spamton chuckled as he gently scratched the antennas with his finger. They were twitching badly in his hands.
"Pfft--hheeheehh--hAHAHAHAHAHAH!! *snort* HAHAHAHHA!!" Tenna couldn't keep the giggles anymore and they gushed out of his mouth, "HAHAHAHAHAHAHAH!!"
"There's that [award winning smile]!" Spamton teased, squeaking when Tenna lost his balance, laugh-snorting loudly a loud belly laugh as he even started to gently stroke the amplifier.
"I give! I give!" Tenna squealed as he felt both his amplifier and antennae tickled. Such a light touch, but it was too much. He's even prefer having his second worst spots tickled than this.
As soon as Spamton let go of his antenna, Tenna swiftly grabbed the addison while he snarled threateningly.
"Now you must pay, you worm!" Tenna growled as he noticed how Spamton looked scared for a moment.
"[Do your worst, Big Boy!]" Spamton purred. Tenna was flustered for a moment before he gently took a wing by his fingers and began to gently tickle them with his fingers.
"That's what you get for angering me!" Tenna gave a warning growl as he gently spidered his fingers over the wing, a smile threatening to form as Spamton began to cackle loudly.
The TV was so busy tickling the addison's wings that he didn't notice a familiar pink robot sneaking up on him before he suddenly felt a feather-like touch one of his antenna.
"Eee!! HAHAHA!!" Tenna burst into giggles as he buckled from the surprise tickle. He collapsed onto the ground and curled into a tight ball, letting go of Spamton as he did so.
"Oh no, you don't!" Mettaton chuckled before he started to tickle both Tenna and Spamton with feathers. He attacked their upper bodies and worst spots at various speeds.
"NOOHOOT THERE!" Tenna squealed as Mettaton's feathers attacked his sides and every other ticklish spot.
"[HAVE MERCY!]" Spamton cackled as the feathers attacked his wings, back and shoulder blades.
"But why? You two ignored me all morning, darlings," Mettaton huffed as the feathers danced.
He tickled them for a few more minutes before he stopped.
"You want attention? I'll give you attention!" Tenna chuckled darkly before he grabbed Mettaton by his sides and attacked them with his fingers.
"No! No--EEHAHAHHAHAHAH!!" Mettaton snort-laughed as his poor sides were attacked. He tried to hide his face with his hands, which allowed the tv show host to attack his armpits.
"[Wait for me!]" Spamton giggled before he helped Tenna.
