Who's the baby, Killua?

[His taunt comes out extra snide in Killua's deeper voice as he rubs down his glans to that sweet spot on the underside of his dick, pumping it roughly with his thumb rubbing circles against swollen veins. This is what makes him cum the fastest when he's alone, so it's perfect to use on his own body.

Underneath Gon's butt, Killua's own member sticks up, nudging against it. Gon ruts his hips forward, eagerly sliding his dick against his own ass.]