Over the years it has been my privilege to be an Op here I have been involved in more than a few incidents, many of which have required logs to be provided. You will be stunned, I think and hope, at just how many of those, when reported, state that 'I told to stop but they kept right on and I can no longer deal with them ...'or words to that effect devolve down, when the actual logs are read to actually being a general trend of wibby-wobbly language neither nay- or yea-saying and in many cases, to the unbiased eye, being bordering on encouraging.
If, in PM or OOC, something distresses you, upsets you, or hits any of the wrong buttons, then you need to let the person know. You don't have to don the bots with the pointy toes and sharp heels to wade in kicking ass, etc., etc. If you already in PM with them, fine. If not and it's in OOC, ask to PM them unless it's a forbidden topic within TLI in which case hail an Op (if no Op is available comment in OOC that you think that topic is not allowed).
Once in PM with them, ask that they stop as what they are doing is not to your taste, interest, etc. Don't beat about the bush and includes it in other sentences. Just state, in a single post, "Please stop, I am not happy with this.' Or words very close to that.