If I'm looking for friends, and I say I'm looking for friends, then I'm looking to meet people that could be friends.
While I take people at their word, I know that some people constantly speak in euphemisms and often they only hear things in euphemisms.
I've spent a lot of time with people to whom I've stated that "What I said is exactly what I meant. No more. No less." Yet they go on assuming. You can't change these people and it's a waste of time to try.
I wouldn't get off on someone's advances if I weren't attracted at some level. Now, more specifically, in a relationship, I'm monogamous when I say I am. I'm clear about it. If I say I'm not monogamous yet, I'm not. If I say I am, I am. When it comes to something important like this, it's important to be clear, honest, and accept the answer.
If my lips say no, it doesn't matter WHAT you think my eyes say or what you think I meant. If you though I meant something other than what I explicitly said, the onus is yours to clarify, not mine.
This is how I approach relationships, regardless of whether it's my bf or a friend.
In the response to the 'nerd' appearing guy (which I tend to assume is me in most situations) offering a message. If your not sure or uncomfortable that your 'sending the wrong signal' then simply turn it down, otherwise, state that you only want and expect a clinical message to relieve muscular pain and not sexual tension.