To people who say this, as someone who has been there, reasons you might find yourself wanting to say "you can do whatever you want to me":
It feels flirty (situationally dependent. This is not the use OP is talking about but make sure you've *already negotiated* before, don't say it in response to genuine questions. If anything else on this list feels true to you, don't let being flirty be an excuse to say it anyway/not communicate/not address those other factors.)
Wanting to please/prioritize your partner (not a bad desire, but they likely want a clear understanding of your own wants and limits so that they can not only do what they want to do but have the Impact they want.)
Fear of seeming too needy, demanding, not submissive enough (maybe ask for them to share some of their desires and limits first so it doesn't feel like you're leading the conversation right out the gate, and understand that you having to trust that if you ask for something they don't care for they'll say no is the same trust they have to have in you.) (note- some Doms DO complain about subs being demanding, or asking for things right out the gate, treating them as kink dispensers. Subs Can be shitty like that and it's fair to complain, but also Doms can do this unreasonably, and in either case people overhearing these complaints can absorb that "don't be demanding, treat your Dom as a person" incorrectly as "don't ask for things")
Not knowing what you want (generally you can just state this outright, I recommend including a request for suggestions or brainstorming, or a discussion of a kink tasting, "Can we try a couple things and see what clicks?" If they're not up to work with you on figuring it out then you will have to just figure out what you want by yourself or with someone else.)
Decision fatigue/desire to set aside making choices (you can in fact also say this bluntly. Being offered a simple two options to pick between works for some people, so you can suggest that as a starting point. You may also need to get some down time to start with, prior to subbing. Subspace is not a replacement for self care and the human need for relaxation. It can help with decision fatigue to have time in subspace, so before doing more in depth scenes needing signifact negotiating you can do smaller ones to help that, but you do need to make Some decisions and do communication upfront for that even if you find ways to safely minimize the decisions to start with. You could ask for suggestions and make the only decisions be indicating your interest/lack, fill out kink interest worksheets so it's on paper instead of a conversation and can be broken up into more manageable chunks, or do a tasting type scene where all you say is yes and no. Seriously try to give yourself downtime and meet your needs without Just putting them on another person though.)
Shame about expressing desires (let yourself be embarrassed. Turn red, stammer, say "I need a minute", push yourself to voice at least one thing. You don't need to be suave in a negotiation, and most Doms will find it cute/hot. And probably do some reflecting on where that shame comes from, how it does and doesn't align with your values, and unpack that some with a professional or at least a trusted friend.)
Fear of setting boundaries/voicing limits (this is a serious one. If you can't do this in the negotiation do you think you can safeword in the moment? You simply Have to find a way to set those boundaries to be able to play. That's not to say you can't Work on this while in a kink relationship, but you need to start working on it Now, and make sure that your Dom understands that that's where you're at and is okay with being in those troubled waters with you. Do Not Be Shitty if they are not up for it. Let them leave without guilting them.)
Lack of concern about your own wellbeing (first of all goddamn do I get it. Depression is hard, ideation warps perception of everything, trauma can destroy your sense of self preservation, I used to think trusting someone meant not minding if they did hurt you rather than having faith that they won't. If you can't find it in you to care about not being hurt for your own sake, care about it for theirs. They almost certainly don't want to trigger you, hurt you in a way you dislike, abuse you, or kill you. If they do want to do those things then you saying what you don't want won't stop them, so in that case it doesn't matter. But they probably don't, that's why they're negotiating with you. Your lack of concern doesn't outweigh their concern for your wellbeing, so let them know the relevant info.)
Thinking about what fits here can get you to a place to address issues, accomodate your needs, and communicate effectively.
