Don't know about Sihanoukville, but in Siem Reap the tuk-tuk touts shout across the street: "Hello Sir, what to you want: boy, girl, marihuana?".

In Pattaya it's a bit more subdued, but whenever I walk along Beach Road and make eye contact with a male there, he makes a fist and points his thumb to his mouth, and I don't think he is offering to suck my dick.

No personal experience, but I assume everything sold there is overpriced and poor quality, you can as well smoke a hemp rope.