Finding someone for sex from a sex related site is not a big thing. All you want to be patient and time. Yeah strategies and approaching methods also doing something but that is not a big deal. If you need a girl to have sex yeah you can find it. But you would not know is she or him is really you were looked. Definitely not. So my advice do not hurry to make your decision. Take it slowly. Get to know each other well. Give them a call. Just tell truth about your situation. If you are married, you have a bf or gf or you can't keep in touch in any special occasions let other person know. If you are looking for nsa fun tell other people how you want it. But you need to be more careful about health when you doing nsa. Also do unsafe sex. Also do not do oral sex if you are not 100 percent sure about other party. Before having sex or any other physical attachment meet him, her or them in place you can talk freely. Buy something to drink. Discuss something about yourself smile and then you can decide are they ok to have fun.
In sri lanka you may feel it may be difficult. But do not overthink. If you are working in Colombo or just think your daily route is Gampaha to fort by train do not make a place near to your route or work place to meet that stranger. Do not go for over crowded place. Google a small restaurants that you can go there with 300 rupees. And have a good session of first date. You can do it more than one time. So do not think first meet is OK. If you uncomfortable let that person go try another one.
Cheers for your next date.
C u.