I don't think Ts get grossed out when clients tell them they have crushes or feelings for them at all. It is not unusual for clients to feel this way and most of them know how to handle it. I don't think it's necessary to share the details of your sexual fantasies, however. Just telling them you fantasize about them is sufficient. It's not saying anything bad about a client who wants to share fantasies, but I think it's up to the T to set some kind of boundaries about what would be shared and what would be kept private should this happen outside of therapy. I think Ts that push for detailed information do so for their own gratification, not for the client.