Don't think you'd have to admit your tickling kink, unless you did (or think you did) admit it to him/them. But I'm no lawyer, don't even play one on TV.
Sorry to hear this. I'd agree with rdhd though. I don't think any admission of your kink is necessary unless it somehow came up in conversation with the rapist.
If you don't mind my asking, was the rapist one of the bullies, or was he unconnected?