I dunno, I think "No," is a great approach. I bet with a little practice you can become an expert.
I remember some of your posts about the ex and this woman. I would have dotted her eye by now, so be cheered in knowing you're doing better than Transformie. If that's any consolation at all...
Lately, I've been enacting a new policy in my life. It goes like this:
Sort out honestly, with myself, what my boundaries are.
Communicate those boundaries to others
Enforce them when they're not respected.
It's tricky but Holy Hell is it better than everything else I've been doing-which is mainly not creating boundaries and then feeling victimized and angry about it.