If you're unable to bring up touch in a general sense, perhaps you could bring it up specifically related to flashbacks. You could tell your T that when you have flashbacks, you've found that the only thing that really grounds you and helps you come out of them is being touched. Tell your T exactly where and how she should touch you (i.e. a tap on the back of the hand or firm grip on your shoulder or lightly shaking your knee...whatever). That might open the door for further conversation, but wouldn't be such a huge "will you touch me" topic.