Oh, the £1m question! Mine asks "what do you need" or "what do you need from me?" and I find them the most difficult questions to answer ever. Usually my answer after a long pause is "nothing". Sometimes it's "I don't know." I think though that even these answers probably tell a therapist something - if I don't know what my needs are or if I do know but can't ask/don't know how to express them, that is probably useful info for my therapist.
She doesn't ask me so much anymore as I told her a few times that I never know how to answer and that, whenever she asks, my mind goes blank and I start to panic. So, I think she started to think that asking the question was counter-productive if it induced anxiety! But, every now and again, up the question comes again and it floors me just the same as always...
Perhaps try to let go of the belief that you're "supposed" to be replying in a certain way as this implies that you think there's a "good" or "right" answer. So, for instance, if you let go of the thought that you're "supposed to have a poignant answer" what would that mean for you? It might give you more permission to ask for some other kind of non-poignant thing. And she might be able to help with that. You did that with the coffee and nap answer (though I get the feeling that you maybe thought that was a flippant answer and that, therefore, it was wrong/not what you were supposed to say?) But - you asked for that because you knew you felt tired, so what you really needed was a rest (a nap) but because you were with her at that time, the alternative was something to pep you up (the coffee) and she met that need for you by sharing hers with you.
I honestly don't think you need to be concerned that she's asking you the question because she's run out of ideas herself. I'd say she's probably wanting to see if you know/can express your needs and then, if you can and she can help meet the need, I think that's what she wants to be able to do. Of course, she may not be able to fulfil every need you ever express there and then herself - but she may be able to help you work through how to get that need met elsewhere/some other way/from yourself.
So - I would try to go back to basics with it and not over analyse what you're "supposed" to say - keep it simple. Unless you have something poignant, in which case, say that ;-) I guess simple things in the moment could be things like: a hug (doesn't have to be asking for a hug from her); some comfort (whatever that may mean for you - physical touch, comforting words, just someone's presence - and again it doesn't have to be from her); a snack because you're hungry/your energy has dropped/you're finding it hard to concentrate; a cushion because you don't feel very comfy; some air (window to be opened or 2 mins outside then come back in); to stand up for a bit because you feel stiff/stuck; to change the subject and talk about something different for a little while; to just sit quietly for a bit and not feel pressure to talk...
But I also think"I don't know" is a very valid answer. And if it has become a default answer and you haven't really actively tried to tune in to what you might need, this might be a good opportunity to try to dig around a little to see what comes up. And if you still don't know, that answer is definitely good enough. As is "I've no idea how to answer that question....what am I supposed to say?" - that could lead to an interesting discussion if you say it in such a way that it opens up a conversation rather than shutting it down.
And please know that I really, really struggle with all this stuff - not knowing how to answer this question, not generally knowing what I need, not knowing how to express it if I do know, not actually wanting to show/admit that I need anything because I hate "feeling needy", thinking there must be a "right" answer so wanting to say the thing I "should" say... I understand the frustration that comes with all that. But I think sometimes we put more pressure on ourselves than we need to and that doesn't help in this whole, difficult process.
