From my understanding:

If you and service provider just look at each other and instantly faham what to do without asking question about how you two found each other or how much, it's not illegal.

If you look for advertisement and found service provider and ask hey you got do this ah, it's illegal.

If service provider put up advertisement saying here got provide this service, it's illegal.
From the article:

You may be caught looking for prostitutes

Aside from section 372 prohibiting pimps from advertising prostitution, it also prohibits you from seeking information for the purpose of prostitution or to accept advertisements, notices or displays related to prostitution:

"...seeks information for that purpose or accepts such advertisement or notice for publication or display;"

Further to the above, you can also be caught for solicitation but this is where things get murky. While section 372B covers the solicitation of prostitution, it is unclear whether Malaysia's legal definition of solicitation includes looking for prostitutes.

To start off our explanation for section 372B, let's first look at what the section says exactly:

"Whoever solicits or importunes for the purpose of prostitution or any immoral purpose in any place shall be punished with imprisonment for a term not exceeding one year or with fine or with both."

The key words to look at in this section are "solicits" and "importunes". A quick look at Merriam-Webster's law dictionary seems to indicate that importune is a synonym of solicit and they both carry the meaning of persuading someone to engage in prostitution. Another reference to Oxford's Dictionary of Law (Eighth Edition) tells us that solicitation can either be the act of a prostitute attempting to obtain clients in a public place or the act of a person trying to obtain prostitution services in a public place.