Are you wanting to just practice hearing 'no' from T and then talking about the feelings that raises for you? I'm also someone who hates to hear 'no' in the sense that it makes me feel like a bad person for wanting something that I shouldn't have or being too needy. It is interesting, however, to think about doing it as an exercise with T. Doing it in a safe way. Like asking my T (her office is in part of her home) "Can I walk through your home?" I know she would probably say 'No' and I would feel bad for asking but we could talk about why I feel bad and where that comes from. I think you should try it! Especially if you and T talk about it beforehand. Good luck!!