Of all the things I think are wrong with bill C-36, defining a sexual service isn't one of them. Case law has already provided tests on how Courts should interpret if a something is prostitution - basically if an "sexual act" was performed for money. There is just no way for the law to define what is a sexual service in all instances. It just won't be realistic for the law to have an appendix with a list of blowjob, handjob, intercourse, fetish abc, etc. It would be too rigid to have any real purpose. I believe case law already has a test whereby if a random bystander saw the act take place, would they believe the act to be sexual. While obviously subjective, I think it does represent a reasonable starting point for the courts to make a determination. Similar tests are made for sexual assault whereby the test is whether or not the victim felt the assault was sexual in nature. People need to realize the law is rarely black and white in the criminal realm. That is only the case for regulatory law like speeding. For criminal law, there only must be sufficient enough precision so that someone would reasonably know what is legal and illegal behavior. I think most people selling a sexual service know they are selling it.