Well I'll take one right now. [He leans over and plants a soft kiss on Gon's lips. Lingering for a moment before pulling away slight. He whispers loud enough for Gon to hear.]

I want one kiss for every time you make me worry, I want one kiss every time you piss me off, and I want one kiss when you make me happy.
[His eyes shine with mischief, with a smirk he finishes.] I want one kiss for causing me to fall for you. But to do all that you'll need to be my boyfriend first~

[While he sounds confident, Killua is nervous wreck on the inside.]