Since Gon and Killua went their own separate paths, they got each other’s contacts and also got plushies of each other… The plushie’s have a special button that when clicked, it makes the other plushie glow and say “I love you”. Killua was in his bedroom with Alluka (they both are staying at a small house together). Killua was listening to Alluka talk, but she was interrupted when the Killua’s plushie of Gon glew and said “I love you”…

Back with Gon, Gon was his room, laying bed with his Killua plushie. Spamming the button so Killua’s Gon plushie kept going “I love you… I love you… I love you… I love you..”

Alluka gave Killua the “Are you serious?” face expression. Killua grabbed the Gon plushie.

Alluka: “Seriously, brother?”