I've made a post tackling this before, but I want to clarify this about Hisoka:

Hisoka's sexual urges/primal needs are DIRECTLY tied to his need for dominance and superiority.

His need for dominance is shown time and time throughout the series.

He tells Gon he can't wait to "break" him.
He tells Chrollo that his fav part in a fight is when the opponent crumbles to his/her knees.

The stronger the opponent, the bigger the feeling of dominance he gets.

Dominance is inherently tied to sexual urges, and since Hisoka lives for this and is an extreme example, we see him doing sexual stuff all the time.

People call him a "pedophile" but that's an extremely reductive word to use on him.

His sexual urges do not extend to just Gon and Killua, but to anyone he deems strong and can make him feel a strong sense of dominance.

I know what you're thinking:

What about the scene where he stares at Gon and Killua's butts in Greed Island?

Or what about the time he tells Illumi he wants to rape Killua?

Those tie into dominance as well.

Raping someone is a form of dominance over them.

You are exerting your superiority or control over someone physically. It gives you a lot of pleasure.

Him staring at Gon and Killua's butts and asking to rape Killua makes perfect sense when you understand this.

His current motive in the manga, revenge, is also tied to dominance.

Hisoka seeks revenge on the Spider because he was denied his "ultimate high" in his fight with Chrollo.

He says he will now decide the place and time, and he will proceed to pluck the Spider one by one.