Mentioning suicidal ideations usually gets me the medication talk lol
Honestly though, I don't have many issues talking about suicide in session. I think what helps me is that I'm in therapy primarily for social anxiety disorder, and when depression comes up it's always in relation to my anxiety. In addition, I never share what plan I have ("I'd rather not say"), and admit that I am worried about being sectioned when it comes up. They've tried to coax me into revealing methods/plans but I stay pretty firm on staying quiet.
I will reveal my previous plans, and the details of my previous really bad suicidal bout years ago. I will admit that I only really think of killing myself a couple years from now (which is true). I won't say that I looked up methods recently, but that I know which methods are lethal and what I would prefer. I have only come close to writing a note once and that was years ago. I would never, ever say that I've written a note in therapy. I also wouldn't say that I browse this forum. When I mention things I've read on here, I would say I read it on reddit or a social anxiety forum. Which is half-true since I first found out about pro-choice on the SS subreddit.
The risks go up if you self-harm or have been sectioned before, which really sucks since those are the populations who would really benefit from being able to talk about these feelings. If you have other mental illnesses you'd like to work on it will really help to come in with that as your primary goal and reveal the suicidal thoughts later as they become relevant.
It also helps not to be argumentative, preachy, or stubborn on pro-choice matters. My current therapist usually brings up the fact that depression can cause a lot of distortion in my life when I bring up suicide. I always hear her out and then say, "I understand it's unreasonable. But I think it's true that I'm not living a fulfilling life. I'm saying that because I've thought about it logically, while I was happy and sane. I believe people should be able to decide this for themselves." The topic usually changes after. I do have a good amount of impairment due to the SA so my therapist seems to see where I'm coming from when I mention that.