The thing with Sri Lanka, you can always ask the bell boys/ladies at your hotel. I casually once asked, and I got directed to another person who deals in all of this. Its a very hush industry in Sri Lanka, so it would be quite difficult. Also if you are staying at a resort, you can always arrange a girl to your room through them but be casual about it and just talk as if you are jokingly asking rather than a serious enquiry...it is a hit and miss in my personal experience. My experience is from a 2017 trip.
